Materiały źródłowe

• #1 Diagnosis for Flu | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/testing/index.html

  Flu is a contagious respiratory illness that can cause fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and/or fatigue. […] There are multiple tests that can detect flu viruses. […] Although testing is the only way to know if you have flu, your doctor may diagnose you based on your symptoms. […] If your doctor needs to know for sure whether you are sick with flu, there are laboratory tests that can be done. […] A number of tests are available to detect flu viruses in respiratory specimens. […] The most common are called „rapid influenza diagnostic tests (RIDTs).” […] Other flu tests called „rapid molecular assays” detect genetic material of the flu virus. […] In addition to RIDTs and rapid molecular assays, there are several more accurate flu tests available that must be performed in specialized laboratories, such as hospital and public health laboratories.

• #2 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #3 Diagnosing Influenza | NYU Langone Health

  https://nyulangone.org/conditions/influenza/diagnosis

  Most of the time, a doctor can diagnose influenza, or the flu, based on your symptomsespecially when they occur in January or February, the peak months of flu season. Symptoms include fever, chills, fatigue, body aches, cough, sore throat, and a runny or stuffy nose. […] A fever, body aches, fatigue, and cough are more common with the flu, and they often come on suddenly. […] Your NYU Langone doctor may order tests to confirm that you have the flu if youre in the hospital or youre at risk for complications. […] An influenza test helps doctors determine if you have the flu virus. Your doctor wipes the inside of your nose or back of your throat with a swab to obtain a sample of nasal secretions or mucus, then sends the sample to a lab for testing. The results enable a doctor to distinguish the flu virus from other respiratory infections with similar symptoms, such as adenoviruses and non-polio enteroviruses.

• #4 Flu (Influenza): Causes, Symptoms, Types & Treatment

  https://my.clevelandclinic.org/health/diseases/4335-influenza-flu

  Your provider diagnoses the flu by listening to your symptoms and testing a sample of mucus from your nose. Theyll put a long stick with a soft tip (swab) in your nose to test for influenza. Results may take a few minutes or your provider may send the sample to a lab, where youll get results in a day or two. […] Providers can treat the flu with antiviral medications under certain circumstances. Antivirals can reduce your risk of severe illness and shorten the amount of time youre sick. Many people can treat the flu without prescription medications. Providers prescribe antivirals if you: […] Antiviral drugs for influenza include: […] Tell your provider about any health conditions you have before starting an antiviral medication. […] If you think you have the flu, its important to get tested early on so that antiviral medications are most effective if your provider prescribes them. Contact a healthcare provider right away if: […] No, gastroenteritis, commonly called stomach flu, isnt caused by the influenza virus. Its not related to the seasonal flu.

• #5 Influenza: Diagnosis and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2019/1215/p751.html

  Influenza is an acute viral respiratory infection that causes significant morbidity and mortality worldwide. […] For most patients in the outpatient setting, the diagnosis is made clinically, and laboratory confirmation is not necessary. Laboratory testing may be useful in hospitalized patients with suspected influenza and in patients for whom a confirmed diagnosis will change treatment decisions. Rapid molecular assays are the preferred diagnostic tests because they can be done at the point of care, are highly accurate, and have fast results. […] According to the CDC, influenza testing can be considered when the results will modify management or when a patient with signs or symptoms of influenza is hospitalized. […] There are several types of point-of-care diagnostic tests for influenza. In otherwise healthy outpatients, more expensive rapid molecular assays may be preferred because of their higher sensitivity compared with other rapid testing methods.

• #6 Influenza: Diagnosis and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2019/1215/p751.html

  In outpatient and emergency department settings, testing for influenza virus is not necessary to start antiviral treatment in a patient with suspected influenza infection, especially during seasons when influenza A and B viruses are circulating in the local community. […] A symptom-only clinical prediction rule may aid clinicians in diagnosing influenza.

• #7 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #8 Influenza Tests – Testing.com

  https://www.testing.com/influenza-testing/

  In contrast, if you have severe symptoms, are being hospitalized, or have an elevated risk of developing life-threatening complications, you are more likely to have flu testing. […] The results from a flu test are reported as either positive or negative. […] Interpretation of your results involves more than just seeing whether the test was positive or negative. […] These considerations are important because no flu test is 100% accurate in identifying influenza infection. […] Several factors can play an important role in the possibility of a false-negative or false-positive result on influenza tests. […] The doctor reviews these factors and your symptoms when deciding whether you should be diagnosed with the flu. […] In general, a positive test result is suggestive of an influenza infection, but does not always mean that you actually have the flu.

• #9 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #10 8. Diagnosis and Treatment of Influenza | ATrain Education

  https://www.atrainceu.com/content/8-diagnosis-and-treatment-influenza-0

  The Infectious Disease Society of America states that antiviral treatment should start as soon as possible for adults and children with documented or suspected influenza, irrespective of influenza vaccination history, who meet the following criteria (Uyeki et al., 2018): […] Persons of any age who are hospitalized with influenza, regardless of duration of illness. […] Outpatients of any age with severe or progressive illness, regardless of the duration of illness. […] Outpatients with chronic medical conditions and immunocompromised patients. […] Children younger than 2 years and adults 65 years. […] Pregnant women and those within 2 weeks postpartum. […] Antiviral treatment should be considered for adults and children who are not at high risk of influenza complications, with documented or suspected influenza, irrespective of influenza vaccination history, who are

• #11 Influenza Tests – Testing.com

  https://www.testing.com/influenza-testing/

  Influenza tests can serve several different purposes for both individual patients and the overall population. […] In individuals, flu tests are used mainly to diagnose whether a person has an influenza virus infection. This can help doctors determine the cause of the symptoms and differentiate between the flu and other viral or bacterial infections. […] For certain patients, diagnosing influenza can help optimize and speed up treatment and avoid unnecessary or unhelpful medications. […] Identifying an influenza infection may also help slow the transmission of the virus. […] On a population level, influenza testing can help evaluate the type of virus, including the type or subtype of influenza, that is having the greatest effect in a community. […] In many cases, especially if you have mild symptoms or are not at high risk of complications, a flu test is unnecessary because it will not change the course of your medical care.

• #12 Influenza (flu) – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/flu/diagnosis-treatment/drc-20351725

  To diagnose the flu, also called influenza, your healthcare professional does a physical exam, looks for symptoms of flu and possibly orders a test that detects flu viruses. […] A flu test may be done by a pharmacy, your healthcare professional’s office or in the hospital. For people age 2 and older, a test you can take at home may be available. […] Types of flu tests you may have include: […] Molecular tests. These tests look for genetic material from the flu virus. Polymerase chain reaction tests, shortened to PCR tests, are molecular tests. […] Antigen tests. These tests look for viral proteins called antigens. Rapid influenza diagnostic tests are one example of antigen tests. […] It’s possible to have a test to diagnose both flu and other respiratory illness, such as COVID-19, which stands for coronavirus disease 2019. You may have both COVID-19 and influenza at the same time. […] Overview of influenza testing methods. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/professionals/diagnosis/overview-testing-methods.htm. Accessed Aug. 19, 2024.

• #13 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #14 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #15 Influenza Rapid Diagnostic Tests – Medical Clinical Policy Bulletins | Aetna

  https://www.aetna.com/cpb/medical/data/400_499/0476.html

  Most of the rapid diagnostic tests that can be done in a physician’s office are approximately greater than 70 % sensitive for detecting influenza and approximately greater than 90 % specific. […] Guidelines from the Centers for Disease Control and Prevention (CDC) explain that commercial rapid diagnostic tests can detect influenza viruses within 30 mins. […] The CDC recommends that, because of the lower sensitivity of the rapid tests, physicians should consider confirming negative tests with viral culture or other means because of the possibility of false-negative rapid test results, especially during periods of peak community influenza activity. […] Centers for Disease Control and Prevention guidelines state that, despite the availability of rapid diagnostic tests, collecting clinical specimens for viral culture is critical, because only culture isolates can provide specific information regarding circulating strains and subtypes of influenza viruses.

• #16 Diagnostic Testing of Influenza

  https://www.southcarolinablues.com/web/public/brands/medicalpolicy/external-policies/diagnostic-testing-of-influenza/

  A decision analysis by Sintchenko et al. (2002) concluded that treatment based on rapid diagnostic testing results was appropriate first over empirical antiviral treatment, except during influenza epidemics. When the probability of a case being due to influenza reached 42 percent, the two strategies were equivalent. Further, a separate meta-analysis found that rapid diagnostic testing did not add to the overall cost-effectiveness of treatment if the probability of influenza was greater than 25 to 30 percent (Call et al., 2005; Dolin, 2024a). […] Viral culture is a gold standard for influenza diagnosis, but it is very time-consuming with an average 7-day turnaround time; on the other hand, real-time RT-PCR and shell vial (SV) testing require only an average of 4 hours and 48 hours, respectively. A study by Lopez Roa et al. (2011) compared real-time RT-PCR and SV testing against conventional cell culture to detect pandemic influenza A H1N1. The sensitivity of real-time RT-PCR as compared to viral culture testing was 96.5%, and SV had a sensitivity of 73.3% and 65.1%, depending on the use of either A549 cells or Madin-Darby Canine Kidney (MDCK) cells, respectively.

• #17 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #18 Influenza (Flu): Diagnosis & Treatment | NewYork-Presbyterian

  https://www.nyp.org/primary-care/influenza-flu/treatment

  How is the Flu Diagnosed? Diagnosis In order to diagnose the flu, your doctor will conduct a physical exam. They may use one or more of the following tests to confirm whether you have the flu. […] RIDTs – Also known as rapid influenza diagnostic tests, these can detect the presence of influenza in respiratory specimens. Several RIDTs are commercially available in the United States and can provide results in a very short time frame. However, they are not as accurate as RT-PCR tests, and false positives and negatives are known to occur. […] RT-PCR (or Reverse Transcription Polymerase Chain Reaction) These tests identify genetic material specific to the influenza virus to determine a positive or negative test result. They are highly efficient and can deliver rapid results to patients. […] Rapid molecular assays – These tests are designed to detect influenza virus nucleic acids that may be present in the upper respiratory system. They are able to deliver rapid results (15-30 minutes) with high sensitivity and specificity.

• #19 Influenza diagnostic tests – UpToDate

  https://www.uptodate.com/contents/image?imageKey=ID/69655

  Influenza diagnostic tests for respiratory specimens […] Conventional molecular assays, including real-time RT-PCR and multiplex PCR (nucleic acid detection) have a time to results of 1 to 8 hours and are noted for their high sensitivity and very high specificity. They can differentiate influenza A and B, as well as influenza A subtypes, and multiplex PCR detects other respiratory viruses and bacterial pathogens. […] Rapid molecular assays (nucleic acid detection) provide results in 15 to 30 minutes and also have high sensitivity and specificity. They can differentiate influenza A and B, but cannot differentiate influenza A subtypes. […] Rapid influenza diagnostic tests (antigen detection) have a time to results of less than 15 minutes, but their sensitivity is low to moderate, while maintaining high specificity.

• #20 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #21 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #22 Influenza: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/219557-overview

  Influenza traditionally has been diagnosed on the basis of clinical criteria, but rapid diagnostic tests, which have a high degree of specificity but only moderate sensitivity, are becoming more widely used. The gold standard for diagnosing influenza A and B is a viral culture of nasopharyngeal samples or throat samples. In elderly or high-risk patients with pulmonary symptoms, perform chest radiography to exclude pneumonia. […] Rapid diagnostic tests for influenza that can provide results within 30 minutes can help confirm the diagnosis. […] The gold standard for confirming influenza virus infection is reverse transcription-polymerase chain reaction (RT-PCR) testing or viral culture of nasopharyngeal or throat secretions. However, culture may require 3 to 7 days, yielding results long after the patient has left the clinic, office, or emergency department, and well past the time when drug therapy could be efficacious.

• #23 Influenza diagnostic tests – UpToDate

  https://www.uptodate.com/contents/image?imageKey=ID/69655

  Influenza diagnostic tests for respiratory specimens […] Conventional molecular assays, including real-time RT-PCR and multiplex PCR (nucleic acid detection) have a time to results of 1 to 8 hours and are noted for their high sensitivity and very high specificity. They can differentiate influenza A and B, as well as influenza A subtypes, and multiplex PCR detects other respiratory viruses and bacterial pathogens. […] Rapid molecular assays (nucleic acid detection) provide results in 15 to 30 minutes and also have high sensitivity and specificity. They can differentiate influenza A and B, but cannot differentiate influenza A subtypes. […] Rapid influenza diagnostic tests (antigen detection) have a time to results of less than 15 minutes, but their sensitivity is low to moderate, while maintaining high specificity.

• #24 Current Approaches for Diagnosis of Influenza Virus Infections in Humans

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4848591/

  RT-PCR is the most traditional yet powerful NAT approach for identification of influenza viruses in most diagnostic labs around the world. Considered a gold standard assay for influenza diagnosis, RT-PCR involves three essential steps: (1) extraction of viral RNA from clinical specimens; (2) Reverse transcription of viral RNA to a single-stranded cDNA using the enzyme reverse transcriptase; and (3) amplification of the PCR product is coupled to fluorescent detection of labeled PCR products. […] NGS technology is comprised of several manufacturer-specific platforms that use different sequencing strategies, reagents, and bioinformatics software.

• #25 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #26 Influenza (Flu): Diagnosis & Treatment | NewYork-Presbyterian

  https://www.nyp.org/primary-care/influenza-flu/treatment

  Viral culture – This test involves the collection of respiratory samples for laboratory analysis. These tests take longer to deliver results, often several days, and can help determine specific antigenic and genetic characteristics of the virus. […] Immunofluorescence assays – This test involves using antibodies and fluorescent dyes on a collected sample to allow for the detection of the influenza virus in order to determine a diagnosis.

• #27 Influenza diagnostic tests – UpToDate

  https://www.uptodate.com/contents/image?imageKey=ID/69655

  Direct and indirect immunofluorescence (antigen detection) take 1 to 4 hours and have moderately high sensitivity and high specificity. […] Viral culture, including shell viral culture, takes 1 to 3 days and has moderately high sensitivity and the highest specificity, but is not useful for timely clinical management and is used for public health surveillance. […] Conventional culture takes 3 to 10 days. […] Refer to UpToDate content on diagnosis of influenza in adults and children for additional details about the choice and interpretation of influenza tests. Refer to the United States Centers for Disease Control and Prevention information on influenza testing methods for additional details.

• #28 Influenza diagnostic tests – UpToDate

  https://www.uptodate.com/contents/image?imageKey=ID/69655

  Direct and indirect immunofluorescence (antigen detection) take 1 to 4 hours and have moderately high sensitivity and high specificity. […] Viral culture, including shell viral culture, takes 1 to 3 days and has moderately high sensitivity and the highest specificity, but is not useful for timely clinical management and is used for public health surveillance. […] Conventional culture takes 3 to 10 days. […] Refer to UpToDate content on diagnosis of influenza in adults and children for additional details about the choice and interpretation of influenza tests. Refer to the United States Centers for Disease Control and Prevention information on influenza testing methods for additional details.

• #29 Current Approaches for Diagnosis of Influenza Virus Infections in Humans

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4848591/

  RIDTs are antigen-based tests developed for rapid diagnosis of influenza virus infections in POC settings. These tests use monoclonal antibodies that target the viral nucleoprotein and employ either enzyme immunoassay or immunochromatographic (lateral flow) techniques. […] A more versatile and powerful technology, lab-on-a-chip/microchip (LoC), provides a new route to develop a new generation of POC influenza tests. […] NAT (also known as NAAT) assays are based on PCR and detect virus-specific DNA or RNA sequences/ genetic material rather than viral antigens or antibodies. These tests are far more sensitive compared with the antigen-based serological tests, and can detect viruses much earlier in clinical samples. A variety of different NATs are currently available and used for diagnosis of influenza viral infections in humans.

• #30 Diagnostic Testing of Influenza

  https://www.southcarolinablues.com/web/public/brands/medicalpolicy/external-policies/diagnostic-testing-of-influenza/

  Clinicians should use rapid molecular assays (i.e., nucleic acid amplification tests) over rapid influenza diagnostic tests (RIDTs) in outpatients to improve detection of influenza virus infection. Clinicians should not use viral culture for initial or primary diagnosis of influenza because results will not be available in a timely manner to inform clinical management (A-III), but viral culture can be considered to confirm negative test results from RIDTs and immunofluorescence assays, such as during an institutional outbreak, and to provide isolates for further characterization. […] The 2024 IDSA guidelines for the diagnosis of infectious diseases by microbiology laboratories under viral pneumonia respiratory infections, specifically including influenza, state: Rapid antigen tests for respiratory virus detection lack sensitivity and depending upon the product, specificity. A meta-analysis of rapid influenza antigen tests showed a pooled sensitivity of 62.3% and a pooled specificity of 98.2%. They should be considered as screening tests only. At a minimum, a negative result should be verified by another method.

• #31 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Serological testing for influenza is not recommended for clinical decision-making. […] Proper serological testing for diagnosis of influenza requires paired acute and convalescent sera collected 2-3 weeks apart. […] If human infection with a novel influenza A virus of animal origin is suspected, the local and state health department should be contacted to perform RT-PCR for seasonal influenza viruses and novel influenza A viruses.

• #32 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Serological testing for influenza is not recommended for clinical decision-making. […] Proper serological testing for diagnosis of influenza requires paired acute and convalescent sera collected 2-3 weeks apart. […] If human infection with a novel influenza A virus of animal origin is suspected, the local and state health department should be contacted to perform RT-PCR for seasonal influenza viruses and novel influenza A viruses.

• #33 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  7. The yield of the microbiological diagnosis is inversely related to the time elapsed since the beginning of the symptoms. The earlier the sampling, the higher the yield of the microbiological diagnosis (A-II). […] 8. Blood, plasma, serum, urine, stool, and cerebrospinal fluid are not suitable specimens for routine influenza virus infection diagnosis (A-III). […] 9. Single or paired serum samples for serological diagnosis are only indicated for epidemiological purposes (A-III). […] What test should be used for the microbiological diagnosis of influenza virus infection? […] Recommendations […] 1. Nucleic acid amplification test (NAAT) is the method of choice for the microbiological diagnosis of influenza virus infection. It should be able to identify type A and type B influenza virus. It is advisable to use a test that is able to identify type A influenza virus and distinguish subtypes H1 and H3 (A-II).

• #34

  https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)

  Most cases of human influenza are clinically diagnosed. However, during periods of low influenza activity or outside of epidemics situations, the infection of other respiratory viruses (e.g. SARS-CoV-2, rhinovirus, respiratory syncytial virus, parainfluenza and adenovirus) can also present as influenza-like illness (ILI), which makes the clinical differentiation of influenza from other pathogens difficult. […] Collection of appropriate respiratory samples and the application of a laboratory diagnostic test is required to establish a definitive diagnosis. Proper collection, storage and transport of respiratory specimens is the essential first step for laboratory detection of influenza virus infections. Laboratory confirmation is commonly performed using direct antigen detection, virus isolation, or detection of influenza-specific RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Various guidance on the laboratory techniques is published and updated by WHO. […] Rapid diagnostic tests are used in clinical settings, but they have lower sensitivity compared to RT-PCR methods and their reliability depends largely on the conditions under which they are used.

• #35 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  7. For epidemiological purposes, cases of influenza virus infection should be microbiologically diagnosed, starting at week 40 and ending on week 20 of the following year (for the Northern hemisphere) and by designated reference laboratories, in order to establish the type of virus strain circulating and the moment of initiation of the epidemic period (A-II). […] How should specimens be collected, stored, and transported? […] Recommendations […] 1. Nasopharyngeal (NPS) or oropharyngeal (OPS) specimens collected by using sterile polyester swabs with plastic or aluminum shafts (not wooden shafts) are the preferred samples for non-invasive microbiological diagnosis of influenza virus infection in adults (A-I). […] 2. NPS aspirate or washing is an alternative specimen that can be used for diagnosis. Collection of this specimen is especially well tolerated by children (A-II).

• #36 Flu (Influenza) Test: MedlinePlus Medical TestLock

  https://medlineplus.gov/lab-tests/flu-influenza-test/

  Flu is short for influenza. It is a respiratory infection caused by viruses. Respiratory infections may affect your nose, throat, and/or lungs. Most flu tests check a sample of fluid from your nose or throat to find out if you’re infected with a flu virus. […] Flu tests check for the most common types of seasonal flu viruses, influenza A and influenza B. Some tests are done in a health care setting, such as your health care provider’s office, pharmacies, or outpatient clinics. You can also buy at-home tests. […] There are two main types of tests for seasonal flu: Rapid influenza antigen tests, or rapid influenza diagnostic tests (RIDTs), are the most common flu tests. They check your fluid sample for certain proteins (antigens) found on flu viruses. […] Molecular flu tests are more accurate than rapid antigen tests. They check your sample for genetic material from flu viruses.

• #37 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  7. For epidemiological purposes, cases of influenza virus infection should be microbiologically diagnosed, starting at week 40 and ending on week 20 of the following year (for the Northern hemisphere) and by designated reference laboratories, in order to establish the type of virus strain circulating and the moment of initiation of the epidemic period (A-II). […] How should specimens be collected, stored, and transported? […] Recommendations […] 1. Nasopharyngeal (NPS) or oropharyngeal (OPS) specimens collected by using sterile polyester swabs with plastic or aluminum shafts (not wooden shafts) are the preferred samples for non-invasive microbiological diagnosis of influenza virus infection in adults (A-I). […] 2. NPS aspirate or washing is an alternative specimen that can be used for diagnosis. Collection of this specimen is especially well tolerated by children (A-II).

• #38 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  3. A correct technique for NPS sampling must be highlighted as a factor that directly correlates with the yield of the microbiological diagnosis (A-III) see Fig. 2 at full text in Appendix A. […] 4. Alternatively, saliva specimens may be used but they are associated with a lower yield for microbiological diagnosis (A-II). […] 5. Swabs must be transported to the Microbiology laboratory in sterile transport tubes with virus transport medium. Dry tubes for the transport of samples for bacterial diagnosis are not adequate (A-II). […] 6. Lower respiratory tract specimens (bronchoalveolar lavage or tracheobronchial aspirate, depending on clinical status of patient) should be collected for viral microbiological diagnosis from hospitalized patients with respiratory failure receiving mechanical ventilation, including subjects presenting a sever clinical condition with a previous negative virus detection in an upper respiratory tract specimen sampled during the ongoing infectious episode (A-II).

• #39 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  7. For epidemiological purposes, cases of influenza virus infection should be microbiologically diagnosed, starting at week 40 and ending on week 20 of the following year (for the Northern hemisphere) and by designated reference laboratories, in order to establish the type of virus strain circulating and the moment of initiation of the epidemic period (A-II). […] How should specimens be collected, stored, and transported? […] Recommendations […] 1. Nasopharyngeal (NPS) or oropharyngeal (OPS) specimens collected by using sterile polyester swabs with plastic or aluminum shafts (not wooden shafts) are the preferred samples for non-invasive microbiological diagnosis of influenza virus infection in adults (A-I). […] 2. NPS aspirate or washing is an alternative specimen that can be used for diagnosis. Collection of this specimen is especially well tolerated by children (A-II).

• #40 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  3. A correct technique for NPS sampling must be highlighted as a factor that directly correlates with the yield of the microbiological diagnosis (A-III) see Fig. 2 at full text in Appendix A. […] 4. Alternatively, saliva specimens may be used but they are associated with a lower yield for microbiological diagnosis (A-II). […] 5. Swabs must be transported to the Microbiology laboratory in sterile transport tubes with virus transport medium. Dry tubes for the transport of samples for bacterial diagnosis are not adequate (A-II). […] 6. Lower respiratory tract specimens (bronchoalveolar lavage or tracheobronchial aspirate, depending on clinical status of patient) should be collected for viral microbiological diagnosis from hospitalized patients with respiratory failure receiving mechanical ventilation, including subjects presenting a sever clinical condition with a previous negative virus detection in an upper respiratory tract specimen sampled during the ongoing infectious episode (A-II).

• #41 Flu Test: Types, Purpose, Procedure & Results

  https://my.clevelandclinic.org/health/diagnostics/22716-flu-influenza-test

  Flu (influenza) tests use a respiratory sample, such as a nasal swab, to check for the presence of the flu virus. […] Yes. Flu tests use a respiratory sample to check for the presence of the flu virus. A healthcare provider will insert a long cotton swab deep into your nostril (nasopharyngeal) or around your nasal walls. A flu test is most often done at your healthcare providers office, in a hospital or urgent care clinic, or at certain pharmacies. […] There are different flu tests, including: Rapid antigen, Molecular assays. […] These tests work by detecting a certain flu virus protein (or antigen) in respiratory fluid from your nose. You can get the results of a rapid antigen test within 10 to 15 minutes. Antigen tests arent as accurate as molecular flu tests. […] Molecular flu tests detect the genetic material of the flu virus in a respiratory sample. These tests are more accurate than rapid antigen tests.

• #42 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  3. A correct technique for NPS sampling must be highlighted as a factor that directly correlates with the yield of the microbiological diagnosis (A-III) see Fig. 2 at full text in Appendix A. […] 4. Alternatively, saliva specimens may be used but they are associated with a lower yield for microbiological diagnosis (A-II). […] 5. Swabs must be transported to the Microbiology laboratory in sterile transport tubes with virus transport medium. Dry tubes for the transport of samples for bacterial diagnosis are not adequate (A-II). […] 6. Lower respiratory tract specimens (bronchoalveolar lavage or tracheobronchial aspirate, depending on clinical status of patient) should be collected for viral microbiological diagnosis from hospitalized patients with respiratory failure receiving mechanical ventilation, including subjects presenting a sever clinical condition with a previous negative virus detection in an upper respiratory tract specimen sampled during the ongoing infectious episode (A-II).

• #43 Influenza A and B Antigen, Immunoassay | Test Detail | Quest Diagnostics

  https://testdirectory.questdiagnostics.com/test/test-detail/11177/influenza-a-and-b-antigen-immunoassay?p=r&cc=MASTER

  Alternative Specimen(s): Throat swab. […] Minimum Volume: One swab or 1 mL. […] Collection Instructions: NP swabs: Flocked nylon, Dacron® polyester or rayon-tipped swabs with flexible wire are recommended. Washes and aspirates: Should be added to an equal amount of VCM medium. […] Transport Temperature: Refrigerated (cold packs). […] Reject Criteria: Specimens submitted in transport systems not listed as acceptable • Sources other than those listed as preferred or acceptable • Wooden-shaft swabs • Cotton tipped swabs • Calcium alginate swabs.

• #44 Influenza Tests – Testing.com

  https://www.testing.com/influenza-testing/

  In contrast, if you have severe symptoms, are being hospitalized, or have an elevated risk of developing life-threatening complications, you are more likely to have flu testing. […] The results from a flu test are reported as either positive or negative. […] Interpretation of your results involves more than just seeing whether the test was positive or negative. […] These considerations are important because no flu test is 100% accurate in identifying influenza infection. […] Several factors can play an important role in the possibility of a false-negative or false-positive result on influenza tests. […] The doctor reviews these factors and your symptoms when deciding whether you should be diagnosed with the flu. […] In general, a positive test result is suggestive of an influenza infection, but does not always mean that you actually have the flu.

• #45 Flu (Influenza) Test: MedlinePlus Medical TestLock

  https://medlineplus.gov/lab-tests/flu-influenza-test/

  Your provider can help you decide if you need a test that checks for more than seasonal flu. To decide which test is right for you, your provider will consider your symptoms, medical history, and how widespread different viral illnesses are in your community. […] If you have symptoms of a respiratory infection, a test for common seasonal flu may be used to help find out if the influenza A or B virus is causing your illness. […] If you have flu symptoms, testing can help you decide what to do next, such as starting antiviral medicine, and taking steps to lower your chances of spreading the virus to others. […] The results of your flu test tell you if signs of influenza A or B virus were found in your sample. Your results are usually described as „positive” or „negative.” […] A positive result means you most likely have the seasonal flu.

• #46 Diagnosis for Flu | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/testing/index.html

  During a flu outbreak, a positive rapid flu test is likely to indicate flu virus infection. […] Despite a negative rapid test result, your health care provider may diagnose you with flu based on your symptoms and their clinical judgment. […] After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement. […] There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. […] The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorization for this new test.

• #47 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #48 Flu (Influenza) Test: MedlinePlus Medical TestLock

  https://medlineplus.gov/lab-tests/flu-influenza-test/

  A negative result means you may not have the flu. A different virus or bacteria may be causing your symptoms. But the flu can’t be ruled out. […] To lower your risk of getting the flu: Avoid close contact with people who are sick. Wash your hands often with soap and water. Use an alcohol-based hand cleaner if soap and water aren’t available. Avoid touching your eyes, nose, and mouth. Clean frequently touched surfaces, such as doorknobs and countertops.

• #49 Diagnosis for Flu | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/testing/index.html

  During a flu outbreak, a positive rapid flu test is likely to indicate flu virus infection. […] Despite a negative rapid test result, your health care provider may diagnose you with flu based on your symptoms and their clinical judgment. […] After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement. […] There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. […] The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorization for this new test.

• #50 Influenza Tests – Testing.com

  https://www.testing.com/influenza-testing/

  In contrast, if you have severe symptoms, are being hospitalized, or have an elevated risk of developing life-threatening complications, you are more likely to have flu testing. […] The results from a flu test are reported as either positive or negative. […] Interpretation of your results involves more than just seeing whether the test was positive or negative. […] These considerations are important because no flu test is 100% accurate in identifying influenza infection. […] Several factors can play an important role in the possibility of a false-negative or false-positive result on influenza tests. […] The doctor reviews these factors and your symptoms when deciding whether you should be diagnosed with the flu. […] In general, a positive test result is suggestive of an influenza infection, but does not always mean that you actually have the flu.

• #51 Influenza Tests – Testing.com

  https://www.testing.com/influenza-testing/

  The first step in diagnosing influenza is almost always a physical examination that includes a review of any active flu-like symptoms. […] When other tests are needed, they focus on identifying signs of an influenza infection. […] One important way that influenza tests can be categorized is based on where the analysis is conducted. […] Rapid, point-of-care tests, sometimes called rapid influenza diagnostic tests (RIDTs), are able to determine whether the test is positive or negative without sending the sample to a lab. […] Antigen tests use a sample from the respiratory tract and look for antigens of an influenza virus. […] Molecular flu tests look for traces of genetic material, or DNA, from the influenza virus in a sample from your respiratory tract. […] Viral culture tests are conducted in a laboratory and involve using your test sample to grow more copies of the virus in a vial.

• #52 Diagnosis for Flu | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/testing/index.html

  During a flu outbreak, a positive rapid flu test is likely to indicate flu virus infection. […] Despite a negative rapid test result, your health care provider may diagnose you with flu based on your symptoms and their clinical judgment. […] After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement. […] There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. […] The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorization for this new test.

• #53 Is It Flu or COVID-19? At-Home Combination Tests Can Check for Both > News > Yale Medicine

  https://www.yalemedicine.org/news/at-home-combo-flu-covid-tests

  Its that time of year when a fever, sore throat, and stuffy nose could easily signal flu or COVID-19. […] While at-home tests for SARS-CoV-2, the virus that causes COVID-19, became an important way of detecting coronavirus infections during the pandemic, people may not realize there are also combination tests that check for both SARS-CoV-2 and influenza A and Btypically the most common strains of the flu virus. […] Last winter, the Food and Drug Administration (FDA) granted emergency use authorizations (EUAs) for a number of at-home combined flu/COVID-19 tests. […] The combo tests approved last year under EUAs, including Pfizers Lucira COVID-19 Flu Home Test, can be found online and in pharmacies and typically sell for $25 to $30 for a two-pack. […] Scott Roberts, MD, a Yale Medicine infectious diseases specialist, says an at-home combo test is a useful toolespecially because it can facilitate prompt treatment.

• #54 Is It Flu or COVID-19? At-Home Combination Tests Can Check for Both > News > Yale Medicine

  https://www.yalemedicine.org/news/at-home-combo-flu-covid-tests

  With access to an at-home test, people can test themselves sooner and call their doctor for a prescription. […] If they arent interested in antiviral therapy or are outside the window of time in which it would be useful, knowing a diagnosis of flu or COVID-19 is helpful in other ways. […] Similar to at-home COVID-19 tests, a combo test includes a nasal swab that you use to collect a specimen from each nostril. […] For both flu and COVID, I would recommend testing at symptom onset and, if negative, retest in 48 hours, Dr. Roberts says. […] These tests are for people ages 2 and up. […] These are antigen tests, also known as rapid tests. […] A test with lower sensitivity could mean theres more of a chance of a false negative result, Dr. Roberts explains. […] But if sampled correctly, the results are very accurate.

• #55 An Office-Based Approach to Influenza: Clinical Diagnosis and Laboratory Testing | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0101/p111.html

  Vaccination is the primary measure for preventing morbidity and mortality from influenza. During the influenza season, family physicians must distinguish influenza from the common cold and other flu-like illnesses. Signs and symptoms of influenza include abrupt onset of fever, severe myalgias, anorexia, sore throat, headache, cough, and malaise. Clinical diagnosis can be difficult or nonspecific when patients have other symptoms (e.g., stuffy nose, sneezing, cough, sore throat) that can be caused by various respiratory viruses or bacterial pathogens. Family physicians can improve diagnostic accuracy by being aware of the epidemiology of influenza. During outbreaks of influenza, commercially available rapid assays can be used to identify type A and B viruses. On average, rapid in-office tests are more than 70 percent sensitive and 90 percent specific for viral antigens. The results of rapid viral tests can guide treatment decisions.

• #56 An Office-Based Approach to Influenza: Clinical Diagnosis and Laboratory Testing | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0101/p111.html

  Symptoms of influenza-like illness can be caused by multiple respiratory viruses, including respiratory syncytial virus, parainfluenza virus, adenovirus, rhinovirus, and corona-virus. Data indicate that up to 70 percent of patients with influenza-like illness may not be infected with an influenza virus. Once the physician has made the tentative diagnosis of influenza, laboratory testing may be an appropriate confirmatory step. […] Office-based techniques for detecting influenza A and B viruses include enzyme immunoassay and direct immunofluorescence. Using these sophisticated, yet relatively easy techniques, the physician can diagnose influenza A and B in 10 to 20 minutes. […] During the time of year when outbreaks of influenza-like illnesses are common, rapid office testing can be performed to determine if influenza is the cause of a patient’s symptoms, to support clinical decision-making, and to define treatment choices. However, physicians should be aware of the limitations of rapid viral tests.

• #57 Influenza (flu) – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/flu/diagnosis-treatment/drc-20351725

  To diagnose the flu, also called influenza, your healthcare professional does a physical exam, looks for symptoms of flu and possibly orders a test that detects flu viruses. […] A flu test may be done by a pharmacy, your healthcare professional’s office or in the hospital. For people age 2 and older, a test you can take at home may be available. […] Types of flu tests you may have include: […] Molecular tests. These tests look for genetic material from the flu virus. Polymerase chain reaction tests, shortened to PCR tests, are molecular tests. […] Antigen tests. These tests look for viral proteins called antigens. Rapid influenza diagnostic tests are one example of antigen tests. […] It’s possible to have a test to diagnose both flu and other respiratory illness, such as COVID-19, which stands for coronavirus disease 2019. You may have both COVID-19 and influenza at the same time. […] Overview of influenza testing methods. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/professionals/diagnosis/overview-testing-methods.htm. Accessed Aug. 19, 2024.

• #58 An Office-Based Approach to Influenza: Clinical Diagnosis and Laboratory Testing | AAFP

  https://www.aafp.org/pubs/afp/issues/2003/0101/p111.html

  Symptoms of influenza-like illness can be caused by multiple respiratory viruses, including respiratory syncytial virus, parainfluenza virus, adenovirus, rhinovirus, and corona-virus. Data indicate that up to 70 percent of patients with influenza-like illness may not be infected with an influenza virus. Once the physician has made the tentative diagnosis of influenza, laboratory testing may be an appropriate confirmatory step. […] Office-based techniques for detecting influenza A and B viruses include enzyme immunoassay and direct immunofluorescence. Using these sophisticated, yet relatively easy techniques, the physician can diagnose influenza A and B in 10 to 20 minutes. […] During the time of year when outbreaks of influenza-like illnesses are common, rapid office testing can be performed to determine if influenza is the cause of a patient’s symptoms, to support clinical decision-making, and to define treatment choices. However, physicians should be aware of the limitations of rapid viral tests.

• #59 Influenza Virus | Choose the Right Test

  https://arupconsult.com/content/influenza-virus

  Molecular testing is recommended for all hospitalized patients with suspected influenza. Multiplex PCR tests that target a panel of respiratory pathogens, including influenza, are recommended in hospitalized immunocompromised patients. Rapid, Clinical Laboratory Improvement Amendments (CLIA)-waived, near-point-of-care PCR testing is preferred over rapid influenza diagnostic tests (RIDTs) in outpatients. […] RIDTs are not recommended unless more sensitive molecular assays are unavailable. […] Serology should only be used for retrospective epidemiologic investigations and is not recommended for primary diagnosis because of the need for acute and convalescent samples. Testing of a single specimen is not interpretable and has no role in the diagnosis of influenza.

• #60 Diagnosis for Flu | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/testing/index.html

  During a flu outbreak, a positive rapid flu test is likely to indicate flu virus infection. […] Despite a negative rapid test result, your health care provider may diagnose you with flu based on your symptoms and their clinical judgment. […] After evaluating you, your doctor may choose to diagnose you with flu without the need for testing based on your symptoms and his or her own clinical judgement. […] There is a test that will check for seasonal flu type A and B viruses and SARS-CoV-2, the virus that causes COVID-19. […] The Food and Drug Administration (FDA) has given CDC an Emergency Use Authorization for this new test.

• #61 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #62 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #63 Diagnostic Testing of Influenza

  https://www.southcarolinablues.com/web/public/brands/medicalpolicy/external-policies/diagnostic-testing-of-influenza/

  The CDC notes the usefulness of RIDT influenza testing given the rapid testing time (less than 15 minutes on the average) and that some have been cleared for point-of-care use, but they note the limited sensitivity to detect influenza as compared to the reference standards for laboratory confirmation testing, RT-PCR or viral culture. Disadvantages of RIDTs include high false negative results, especially during outbreaks, false positive results during times when influenza activity is low, and the lack of parity in RIDTs in detecting viral antigens. […] The IDSA published an update to seasonal influenza in adults and children in 2018. Here, IDSA propounded the following patient populations as targets for influenza testing: During influenza activity (defined as the circulation of seasonal influenza A and B viruses among persons in the local community) clinicians should test for influenza in high-risk patients, including immunocompromised persons who present with influenza-like illness, pneumonia, or nonspecific respiratory illness (e.g., cough without fever) if the testing result will influence clinical management (A-III).

• #64 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #65 Diagnostic Testing of Influenza

  https://www.southcarolinablues.com/web/public/brands/medicalpolicy/external-policies/diagnostic-testing-of-influenza/

  Yoon et al. (2017) investigated the use of saliva specimens for detecting influenza A and B using RIDTs. Both saliva and nasopharyngeal swab (NPS) samples were analyzed from 385 patients; each sample was assayed using four different RIDTs the Sofia Influenza A+B Fluorescence Immunoassay, ichroma TRIAS Influenza A+B, SD Bioline Influenza Ag, and BinaxNOW Influenza A/B antigen kit as well as real-time RT-PCR. […] The CDC gives two sets of guidelines concerning testing for influenza. If influenza is known to be circulating in the community, they give the algorithm displayed in the figure below (CDC, 2023b): If the patient is asymptomatic for influenza, then they do not recommend testing. If the patient is symptomatic and is being admitted to the hospital, then they recommend testing; on the other hand, if a symptomatic patient is not being admitted to the hospital, they recommend testing if the results of the test will influence clinical management.

• #66 Influenza Rapid Diagnostic Tests – Medical Clinical Policy Bulletins | Aetna

  https://www.aetna.com/cpb/medical/data/400_499/0476.html

  Although widely used in emergency departments and physicians’ offices, antigen-based rapid assays have shown poor sensitivity for the H1N1 virus compared with culture or molecular diagnostic techniques. […] The findings of this performance assessment indicated that, compared with rRT-PCR, the sensitivity of the RIDT for detecting infection in patients with 2009 pandemic H1N1 was 47 %, and the specificity was 86 %. […] The authors concluded that the RIDT had relatively poor sensitivity but excellent specificity in this consecutive series of respiratory specimens obtained from pediatric patients. […] The authors concluded that the findings of this study suggested that multiplex assay is a rapid, valid, and accurate method for the detection of SARS-CoV-2 and influenza viruses in clinical samples.

• #67 Influenza Rapid Diagnostic Tests – Medical Clinical Policy Bulletins | Aetna

  https://www.aetna.com/cpb/medical/data/400_499/0476.html

  Most of the rapid diagnostic tests that can be done in a physician’s office are approximately greater than 70 % sensitive for detecting influenza and approximately greater than 90 % specific. […] Guidelines from the Centers for Disease Control and Prevention (CDC) explain that commercial rapid diagnostic tests can detect influenza viruses within 30 mins. […] The CDC recommends that, because of the lower sensitivity of the rapid tests, physicians should consider confirming negative tests with viral culture or other means because of the possibility of false-negative rapid test results, especially during periods of peak community influenza activity. […] Centers for Disease Control and Prevention guidelines state that, despite the availability of rapid diagnostic tests, collecting clinical specimens for viral culture is critical, because only culture isolates can provide specific information regarding circulating strains and subtypes of influenza viruses.

• #68

  https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)

  Most cases of human influenza are clinically diagnosed. However, during periods of low influenza activity or outside of epidemics situations, the infection of other respiratory viruses (e.g. SARS-CoV-2, rhinovirus, respiratory syncytial virus, parainfluenza and adenovirus) can also present as influenza-like illness (ILI), which makes the clinical differentiation of influenza from other pathogens difficult. […] Collection of appropriate respiratory samples and the application of a laboratory diagnostic test is required to establish a definitive diagnosis. Proper collection, storage and transport of respiratory specimens is the essential first step for laboratory detection of influenza virus infections. Laboratory confirmation is commonly performed using direct antigen detection, virus isolation, or detection of influenza-specific RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Various guidance on the laboratory techniques is published and updated by WHO. […] Rapid diagnostic tests are used in clinical settings, but they have lower sensitivity compared to RT-PCR methods and their reliability depends largely on the conditions under which they are used.

• #69

  https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)

  Most cases of human influenza are clinically diagnosed. However, during periods of low influenza activity or outside of epidemics situations, the infection of other respiratory viruses (e.g. SARS-CoV-2, rhinovirus, respiratory syncytial virus, parainfluenza and adenovirus) can also present as influenza-like illness (ILI), which makes the clinical differentiation of influenza from other pathogens difficult. […] Collection of appropriate respiratory samples and the application of a laboratory diagnostic test is required to establish a definitive diagnosis. Proper collection, storage and transport of respiratory specimens is the essential first step for laboratory detection of influenza virus infections. Laboratory confirmation is commonly performed using direct antigen detection, virus isolation, or detection of influenza-specific RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Various guidance on the laboratory techniques is published and updated by WHO. […] Rapid diagnostic tests are used in clinical settings, but they have lower sensitivity compared to RT-PCR methods and their reliability depends largely on the conditions under which they are used.

• #70

  https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)

  Most cases of human influenza are clinically diagnosed. However, during periods of low influenza activity or outside of epidemics situations, the infection of other respiratory viruses (e.g. SARS-CoV-2, rhinovirus, respiratory syncytial virus, parainfluenza and adenovirus) can also present as influenza-like illness (ILI), which makes the clinical differentiation of influenza from other pathogens difficult. […] Collection of appropriate respiratory samples and the application of a laboratory diagnostic test is required to establish a definitive diagnosis. Proper collection, storage and transport of respiratory specimens is the essential first step for laboratory detection of influenza virus infections. Laboratory confirmation is commonly performed using direct antigen detection, virus isolation, or detection of influenza-specific RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Various guidance on the laboratory techniques is published and updated by WHO. […] Rapid diagnostic tests are used in clinical settings, but they have lower sensitivity compared to RT-PCR methods and their reliability depends largely on the conditions under which they are used.

• #71 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  The Infectious Diseases Society of America (IDSA) recommends use of rapid influenza molecular assays over rapid influenza diagnostic tests (RIDTs) for detection of influenza viruses in respiratory specimens of outpatients. […] IDSA recommends use of RT-PCR or other molecular assays for detection of influenza viruses in respiratory specimens of hospitalized patients. […] Rapid molecular assays are a kind of molecular influenza diagnostic test to detect influenza virus nucleic acids in upper respiratory tract specimens with high sensitivity (90-95%) and specificity. […] Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA or nucleic acids in respiratory specimens with very high sensitivity and specificity. […] Rapid influenza diagnostic tests (RIDTs) are antigen detection assays that can detect influenza viral antigens in 10-15 minutes with moderate sensitivity (50-70%) and high specificity.

• #72 Diagnosing and Treating Flu | American Lung Association

  https://www.lung.org/lung-health-diseases/lung-disease-lookup/influenza/diagnosing-and-treating-influenza

  There are effective treatments that can reduce the duration of the suffering caused by the flu and improve symptoms. […] A doctor’s exam may be needed to tell whether you have developed the flu or a complication of the flu. […] There are tests that can determine if you have the flu as long you are tested within the first two or three days of illness and many providers use antiviral medications when they are confident of the diagnosis. […] Your doctor may prescribe antiviral medication to treat the virus, and over-the-counter medication can be used to minimize discomfort associated with flu symptoms. […] Antiviral treatment can boost your immune system if taken promptly at the onset of symptoms of some infectious respiratory diseases. […] These drugs are approved for early treatment of influenza and have been shown to reduce flu symptoms if started within a day or two of getting sick. […] Antiviral medicine is recommended for people with more severe illness, especially those who might require hospitalization. […] Treatment with antiviral medicine is most important for people with suspected or confirmed influenza who are at higher risk for complications.

• #73 Influenza Virus | Choose the Right Test

  https://arupconsult.com/content/influenza-virus

  Molecular testing is recommended for all hospitalized patients with suspected influenza. Multiplex PCR tests that target a panel of respiratory pathogens, including influenza, are recommended in hospitalized immunocompromised patients. Rapid, Clinical Laboratory Improvement Amendments (CLIA)-waived, near-point-of-care PCR testing is preferred over rapid influenza diagnostic tests (RIDTs) in outpatients. […] RIDTs are not recommended unless more sensitive molecular assays are unavailable. […] Serology should only be used for retrospective epidemiologic investigations and is not recommended for primary diagnosis because of the need for acute and convalescent samples. Testing of a single specimen is not interpretable and has no role in the diagnosis of influenza.

• #74 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  When should resistance to neuraminidase inhibitors be sought? […] Recommendations […] 1. Resistance to neuraminidase inhibitors should be considered when a microbiological diagnostic test continues to be positive more than 8-10 days after initiation of treatment with this type of antivirals (particularly when the antiviral dose is suboptimal) (B-III). […] 2. Resistance to neuraminidase inhibitors should also be considered when a microbiological diagnostic test is positive while on or immediately after prophylaxis with this type of antivirals (C-III). […] 3. Resistance to antivirals should be especially considered in the immunocompromised population with evidence of persistent viral replication (e.g., 7-10 days after initiation of treatment) (B-III). […] 4. Periodic tests to detect resistance in influenza virus from random samples from community circulating virus should be performed. This surveillance should be limited to the reference laboratories designated by regional or national government authorities or by international Public Health organizations (C-III).

• #75 Influenza: Diagnosis and Management in the ED

  https://www.ebmedicine.net/topics/infectious-disease/influenza

  Pregnancy is a risk factor for a more severe disease course during an influenza infection. Initial CDC epidemiologic data from the last 10 influenza seasons indicate that some of the highest rates of morbidity and mortality are among pregnant women, which confirms the necessity of antivirals in this population. […] Even in times of epidemic influenza infection, numerous strains can be circulating at a given time within a particular region. In past epidemics, there have been reports of influenza strains resistant to oseltamivir. Thus, without knowing the prevalence of local strains, one might mistakenly choose an antiviral agent that will prove less effective on those strains. Treatment with more than 1 agent may even be indicated in some regions until more formal strain-specific diagnostic testing can be undertaken. Since certain medications are effective against only influenza type A, the local prevalence of any type B influenza should be determined in order to select the appropriate drug therapy. […] The impact of rapid diagnosis on management of adults hospitalized with influenza.

• #76 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  Recommendations […] 1. Influenza should be suspected in any child that presents acute fever with or without respiratory symptoms during the annual epidemic influenza period (A-II). […] 2. The definition of influenza-like illness (ILI) has a very low diagnostic yield in children, especially in those younger than 5 years (A-II). […] 3. In infants younger than 6 months, influenza may present as a sepsis-like syndrome (A-II). […] Can influenza virus infection be clinically distinguished from other respiratory viruses in a child? […] Recommendations […] 1. Many of the respiratory viral illnesses in children share similar signs and symptoms and although there are clinical differences that are specific to some viruses, physicians cannot usually confirm or rule out a particular viral infection on clinical grounds alone (A-I).

• #77 Executive summary – Diagnosis, treatment and prophylaxis of influenza virus infection – Consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Pediatric Infec

  https://www.elsevier.es/es-revista-atencion-primaria-27-articulo-executive-summary-diagnosis-treatment-S0212656723000628

  7. For epidemiological purposes, cases of influenza virus infection should be microbiologically diagnosed, starting at week 40 and ending on week 20 of the following year (for the Northern hemisphere) and by designated reference laboratories, in order to establish the type of virus strain circulating and the moment of initiation of the epidemic period (A-II). […] How should specimens be collected, stored, and transported? […] Recommendations […] 1. Nasopharyngeal (NPS) or oropharyngeal (OPS) specimens collected by using sterile polyester swabs with plastic or aluminum shafts (not wooden shafts) are the preferred samples for non-invasive microbiological diagnosis of influenza virus infection in adults (A-I). […] 2. NPS aspirate or washing is an alternative specimen that can be used for diagnosis. Collection of this specimen is especially well tolerated by children (A-II).

• #78 Diagnosing and Treating Flu | American Lung Association

  https://www.lung.org/lung-health-diseases/lung-disease-lookup/influenza/diagnosing-and-treating-influenza

  There are effective treatments that can reduce the duration of the suffering caused by the flu and improve symptoms. […] A doctor’s exam may be needed to tell whether you have developed the flu or a complication of the flu. […] There are tests that can determine if you have the flu as long you are tested within the first two or three days of illness and many providers use antiviral medications when they are confident of the diagnosis. […] Your doctor may prescribe antiviral medication to treat the virus, and over-the-counter medication can be used to minimize discomfort associated with flu symptoms. […] Antiviral treatment can boost your immune system if taken promptly at the onset of symptoms of some infectious respiratory diseases. […] These drugs are approved for early treatment of influenza and have been shown to reduce flu symptoms if started within a day or two of getting sick. […] Antiviral medicine is recommended for people with more severe illness, especially those who might require hospitalization. […] Treatment with antiviral medicine is most important for people with suspected or confirmed influenza who are at higher risk for complications.

• #79 8. Diagnosis and Treatment of Influenza | ATrain Education

  https://www.atrainceu.com/content/8-diagnosis-and-treatment-influenza-0

  The Infectious Disease Society of America states that antiviral treatment should start as soon as possible for adults and children with documented or suspected influenza, irrespective of influenza vaccination history, who meet the following criteria (Uyeki et al., 2018): […] Persons of any age who are hospitalized with influenza, regardless of duration of illness. […] Outpatients of any age with severe or progressive illness, regardless of the duration of illness. […] Outpatients with chronic medical conditions and immunocompromised patients. […] Children younger than 2 years and adults 65 years. […] Pregnant women and those within 2 weeks postpartum. […] Antiviral treatment should be considered for adults and children who are not at high risk of influenza complications, with documented or suspected influenza, irrespective of influenza vaccination history, who are

• #80 Flu (Influenza): Causes, Symptoms, Types & Treatment

  https://my.clevelandclinic.org/health/diseases/4335-influenza-flu

  Your provider diagnoses the flu by listening to your symptoms and testing a sample of mucus from your nose. Theyll put a long stick with a soft tip (swab) in your nose to test for influenza. Results may take a few minutes or your provider may send the sample to a lab, where youll get results in a day or two. […] Providers can treat the flu with antiviral medications under certain circumstances. Antivirals can reduce your risk of severe illness and shorten the amount of time youre sick. Many people can treat the flu without prescription medications. Providers prescribe antivirals if you: […] Antiviral drugs for influenza include: […] Tell your provider about any health conditions you have before starting an antiviral medication. […] If you think you have the flu, its important to get tested early on so that antiviral medications are most effective if your provider prescribes them. Contact a healthcare provider right away if: […] No, gastroenteritis, commonly called stomach flu, isnt caused by the influenza virus. Its not related to the seasonal flu.

• #81 Flu (Influenza): Causes, Symptoms, Types & Treatment

  https://my.clevelandclinic.org/health/diseases/4335-influenza-flu

  Your provider diagnoses the flu by listening to your symptoms and testing a sample of mucus from your nose. Theyll put a long stick with a soft tip (swab) in your nose to test for influenza. Results may take a few minutes or your provider may send the sample to a lab, where youll get results in a day or two. […] Providers can treat the flu with antiviral medications under certain circumstances. Antivirals can reduce your risk of severe illness and shorten the amount of time youre sick. Many people can treat the flu without prescription medications. Providers prescribe antivirals if you: […] Antiviral drugs for influenza include: […] Tell your provider about any health conditions you have before starting an antiviral medication. […] If you think you have the flu, its important to get tested early on so that antiviral medications are most effective if your provider prescribes them. Contact a healthcare provider right away if: […] No, gastroenteritis, commonly called stomach flu, isnt caused by the influenza virus. Its not related to the seasonal flu.

• #82

  https://diagnostics.roche.com/gb/en/article-listing/health-topics/infectious-diseases/respiratory-tract-infections/influenza.html

  Identification is essential for infection control and patient management. […] This makes diagnosis based on symptoms alone challenging for clinicians. […] Current diagnostic methods commonly used are point-of-care rapid antigen tests, molecular point of care tests and lab based polymerase chain reaction (PCR) tests. […] Reliable negative results for influenza enable clinicians to consider other causes of illness like bacterial infections that require antibiotics. […] An unmet need exists for lab-quality tests that can accurately rule in or rule out influenza quickly, near patients to inform clinical management. […] Use of molecular point-of-care testing that can reliably detect viral and/or bacterial pathogens would result in enhanced care, less antibiotic empiricism, reduced patient and societal cost of illness.

• #83 Overview of Influenza Testing Methods | Influenza (Flu) | CDC

  https://www.cdc.gov/flu/hcp/testing-methods/index.html

  Influenza virus testing is not required to make a clinical diagnosis of influenza in outpatients with suspected influenza. […] Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to hospital. […] Clinicians should understand the limitations of influenza virus tests and how to properly interpret the results, particularly negative results. […] Diagnostic tests available for detection of influenza viruses in respiratory specimens include molecular assays and antigen detection tests. […] Influenza virus testing can inform clinical management when the results may influence clinical decisions such as whether to initiate antiviral treatment, perform other diagnostic testing, or to implement infection prevention and control measures for influenza.

• #84 Current Approaches for Diagnosis of Influenza Virus Infections in Humans

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4848591/

  RIDTs are antigen-based tests developed for rapid diagnosis of influenza virus infections in POC settings. These tests use monoclonal antibodies that target the viral nucleoprotein and employ either enzyme immunoassay or immunochromatographic (lateral flow) techniques. […] A more versatile and powerful technology, lab-on-a-chip/microchip (LoC), provides a new route to develop a new generation of POC influenza tests. […] NAT (also known as NAAT) assays are based on PCR and detect virus-specific DNA or RNA sequences/ genetic material rather than viral antigens or antibodies. These tests are far more sensitive compared with the antigen-based serological tests, and can detect viruses much earlier in clinical samples. A variety of different NATs are currently available and used for diagnosis of influenza viral infections in humans.

• #85 Current Approaches for Diagnosis of Influenza Virus Infections in Humans

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4848591/

  RT-PCR is the most traditional yet powerful NAT approach for identification of influenza viruses in most diagnostic labs around the world. Considered a gold standard assay for influenza diagnosis, RT-PCR involves three essential steps: (1) extraction of viral RNA from clinical specimens; (2) Reverse transcription of viral RNA to a single-stranded cDNA using the enzyme reverse transcriptase; and (3) amplification of the PCR product is coupled to fluorescent detection of labeled PCR products. […] NGS technology is comprised of several manufacturer-specific platforms that use different sequencing strategies, reagents, and bioinformatics software.

• #86 Influenza Rapid Diagnostic Tests – Medical Clinical Policy Bulletins | Aetna

  https://www.aetna.com/cpb/medical/data/400_499/0476.html

  Although widely used in emergency departments and physicians’ offices, antigen-based rapid assays have shown poor sensitivity for the H1N1 virus compared with culture or molecular diagnostic techniques. […] The findings of this performance assessment indicated that, compared with rRT-PCR, the sensitivity of the RIDT for detecting infection in patients with 2009 pandemic H1N1 was 47 %, and the specificity was 86 %. […] The authors concluded that the RIDT had relatively poor sensitivity but excellent specificity in this consecutive series of respiratory specimens obtained from pediatric patients. […] The authors concluded that the findings of this study suggested that multiplex assay is a rapid, valid, and accurate method for the detection of SARS-CoV-2 and influenza viruses in clinical samples.

• #87 Influenza Virus Testing Methods

  https://www.elisakits.co.uk/blog/influenza-virus-testing-methods/

  Whereas for patients that have been hospitalised then it is recommended to use molecular diagnostics procedures such as RT-PCR, NAATs and various antigen detection tests such as rapid antigen, ELISA and immunofluorescence assays. […] When performing any diagnostic test, the results generated from this assay should always be evaluated in context to other epidemiological and clinical information that is available to any professional healthcare provider. […] There is no single diagnostic procedure that is adequate and suitable for all the different clinical situations. […] Virologists have to select the appropriate protocol that best fits their specific clinical situations, along with the one which will generate the most reliable results.

• #88 Influenza Virus | Choose the Right Test

  https://arupconsult.com/content/influenza-virus

  The Infectious Diseases Society of America (IDSA) and the CDC recommend testing if the results will influence management decisions, such as whether to initiate antiviral therapy. […] Ideally, influenza testing should occur as soon as possible after illness onset, using respiratory specimens collected within 4 days of symptom onset. […] Influenza can be detected by polymerase chain reaction (PCR) tests, direct fluorescent antibody (DFA) stains, rapid influenza diagnostic tests (RIDTs), culture, and serology (which should only be used for retrospective epidemiologic investigations, not for primary diagnosis). PCR is preferred because of its increased sensitivity and specificity. […] Near-point-of-care polymerase chain reaction (PCR) testing offers a more rapid turnaround time than other molecular test types, as well as high sensitivity and specificity, although more complex assays provide greater sensitivity and specificity.

• #89 Influenza Virus | Choose the Right Test

  https://arupconsult.com/content/influenza-virus

  Molecular testing is recommended for all hospitalized patients with suspected influenza. Multiplex PCR tests that target a panel of respiratory pathogens, including influenza, are recommended in hospitalized immunocompromised patients. Rapid, Clinical Laboratory Improvement Amendments (CLIA)-waived, near-point-of-care PCR testing is preferred over rapid influenza diagnostic tests (RIDTs) in outpatients. […] RIDTs are not recommended unless more sensitive molecular assays are unavailable. […] Serology should only be used for retrospective epidemiologic investigations and is not recommended for primary diagnosis because of the need for acute and convalescent samples. Testing of a single specimen is not interpretable and has no role in the diagnosis of influenza.

• #90 Influenza: Diagnosis and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2019/1215/p751.html

  Influenza is an acute viral respiratory infection that causes significant morbidity and mortality worldwide. […] For most patients in the outpatient setting, the diagnosis is made clinically, and laboratory confirmation is not necessary. Laboratory testing may be useful in hospitalized patients with suspected influenza and in patients for whom a confirmed diagnosis will change treatment decisions. Rapid molecular assays are the preferred diagnostic tests because they can be done at the point of care, are highly accurate, and have fast results. […] According to the CDC, influenza testing can be considered when the results will modify management or when a patient with signs or symptoms of influenza is hospitalized. […] There are several types of point-of-care diagnostic tests for influenza. In otherwise healthy outpatients, more expensive rapid molecular assays may be preferred because of their higher sensitivity compared with other rapid testing methods.

• #91 Influenza: Diagnosis and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2019/1215/p751.html

  In outpatient and emergency department settings, testing for influenza virus is not necessary to start antiviral treatment in a patient with suspected influenza infection, especially during seasons when influenza A and B viruses are circulating in the local community. […] A symptom-only clinical prediction rule may aid clinicians in diagnosing influenza.

• #92 Diagnosing Influenza at the Point of Care – QuantuMDx

  https://www.quantumdx.com/tsw/diagnosing-influenza-at-the-point-of-care/

  Influenza, or flu, is a common respiratory infection usually associated with a seasonal increase during the winter months often referred to as flu season. […] This short post explores how diagnosis of influenza at the point-of-care can make a difference to patients and healthcare services. […] Diagnosis becomes particularly important for those in at risk groups who are vulnerable to serious influenza infection and are more likely to require healthcare intervention and/or hospitalisation. […] Implementation of appropriate point-of-care tests for diagnosis of respiratory infections, including influenza, in these community hubs will provide healthcare professionals with the information they need to make an informed clinical decision about the best care/management for a patient. […] The availability of a rapid result indicating a diagnosis of influenza in busy clinical environment means that not only can a healthcare professional make an informed decision about the best treatment plan for the individual patient, but timely infection prevention and control interventions for influenza-positive patients can be taken to protect others in the area from acquiring the infection.

• #93 Influenza Diagnosis | NIAID: National Institute of Allergy and Infectious Diseases

  https://www.niaid.nih.gov/diseases-conditions/influenza-diagnosis

  Because different strains of flu respond differently to available drugs, healthcare providers must be able to quickly distinguish one flu strain from another. NIAID supports research to design diagnostics that are faster, more accurate, more cost-effective, and more portable. […] Today, researchers are developing clinical assays to determine whether influenza viruses are sensitive to neuraminidase inhibitors, a class of antiviral drugs that inhibit release of influenza virus from infected cells. Diagnostics that enable healthcare professionals to quickly distinguish one flu strain from another at the point of patient care and to detect resistance to antiviral drugs would ensure that patients receive the most appropriate care.

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