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• #1 Lab Tests Are Key for Diagnosing Chickenpox | MDedge

  https://www.mdedge.com/edermatologynews/article/268480/infectious-diseases/lab-tests-are-key-diagnosing-chickenpox

  Lab Tests Are Key for Diagnosing Chickenpox […] Data from the Minnesota Department of Health (MDH) underscore the often poor reliability of a clinical diagnosis of varicella (chickenpox) in children without laboratory test confirmation, according to a report featured in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report. […] Only about half of clinically diagnosed varicella cases — cases diagnosed by examining rashes without laboratory testing — were positive for the varicella-zoster virus (VZV), suggesting lab testing is important to avoid consequences such as children being kept out of school longer than necessary. […] Clinical diagnosis continues to be the primary method for diagnosing varicella, said authors of the report, led by Alison Ruprecht, MPH, a state epidemiologist with the MDH. But the signs and symptoms of those who have received the varicella vaccine (including fewer skin lesions, mostly maculopapular) make it difficult to diagnose.

• #1 Chickenpox (Varicella)

  https://dermnetnz.org/topics/chickenpox

  Diagnosis of chickenpox is usually made on the presence of its characteristic rash and the presence of different stages of lesions simultaneously. A clue to the diagnosis is in knowing that the patient has been exposed to an infected contact within the 10-21 day incubation period. Patients may also have prodromal signs and symptoms. […] Laboratory tests are often undertaken to confirm the diagnosis. […] PCR detects the varicella virus in skin lesions and is the most accurate method for diagnosis. […] The culture of blister fluid is time-consuming and is less frequently performed. […] Serology (IgM and IgG) is most useful in pregnant women, or before prescribing immune suppression medication to determine the need for pre-treatment immunisation.

• #1 Chickenpox: Nursing Diagnosis & Interventions | Nurse.com

  https://www.nurse.com/clinical-guides/chickenpox/?srsltid=AfmBOor_fm3rzh7DJvs2IW77sXbsNaZBSNay1hKVGc3YdreeH-FWUXu8

  Diagnosis of chickenpox is primarily clinical, based on characteristic symptoms and physical examination. Diagnostic methods include: […] The typical presentation of chickenpox includes a fever followed by a red, itchy rash that progresses through papules, vesicles, and crusted lesions. The rash initially appears on the face, chest, or back and then spreads to other areas of the body. The rash typically occurs in crops and lesions are in different stages. […] Polymerase chain reaction (PCR) testing of skin lesions or bodily fluids (such as blood or cerebrospinal fluid) can confirm the presence of varicella-zoster virus, especially in atypical or severe cases. […] Antibody tests can be used to confirm past exposure or immunity, particularly in pregnant or immunocompromised individuals.

• #1 Laboratory Testing for Varicella (Chickenpox) and Zoster (Shingles) – MN Dept. of Health

  https://www.health.state.mn.us/diseases/varicella/hcp/labtesting.html

  Testing should be done for all cases of varicella because: Clinical diagnosis is now less reliable. The classic maculopapular vesicular rash is seen less frequently, and rash in vaccinated patients may lack vesicles and resemble other viral rashes or even bug bites. Recommendations for exclusion and post-exposure prophylaxis are diagnosis dependent. […] The MDH Public Health Laboratory (MDH-PHL) and most reference laboratories provide PCR testing for people with suspect varicella. However, MDH requests specimens from lesions or dermal scrapings to be submitted to MDH-PHL for PCR. […] Recommended for testing for immunity. Not recommended for diagnosis of VZV infection. However, a four-fold or greater rise in serum varicella immunoglobulin G (IgG) antibody titer by any standard serologic assay between acute and convalescent sera meets laboratory criteria for current VZV infection.

• #1 Lab Tests Are Key for Diagnosing Chickenpox | MDedge

  https://www.mdedge.com/edermatologynews/article/268480/infectious-diseases/lab-tests-are-key-diagnosing-chickenpox

  The researchers found that among 208 patients receiving a clinical diagnosis of varicella after only examination at a medical facility, fewer than half (45%) had positive varicella-zoster virus (VZV) lab test results. VZV detection was 66% lower in those who received varicella vaccine compared with those who did not. […] “Clinicians should incorporate routine laboratory testing whenever varicella is suspected,” the researchers wrote. “Public health and school health professionals should emphasize the importance of laboratory confirmation in their recommendations to clinicians and parents.” […] Cost is often an issue with lab testing as well as turn-around time and access, he said, and those factors can be barriers. […] But when clinicians aren’t confident in their diagnosis, “I think in those scenarios, testing can be very helpful in terms of management from a treatment standpoint as well as a potential infection control standpoint,” he said.

• #1 Laboratory Testing for Varicella-Zoster Virus (VZV) | Chickenpox (Varicella) | CDC

  https://www.cdc.gov/chickenpox/php/laboratories/index.html

  This varicella-zoster virus (VZV) laboratory testing information applies to testing and diagnosis of primary VZV infection (varicella) and reactivation (herpes zoster). […] Polymerase chain reaction (PCR) is the most helpful laboratory test for confirming cases of varicella and herpes zoster. […] Testing is recommended to: Confirm suspected cases of varicella. […] Confirm varicella as the cause of outbreaks. […] Confirm varicella in severe cases (hospitalizations or deaths) or unusual cases. […] The preferred diagnosis method is a demonstration of VZV DNA by PCR tests from a clinical specimen, ideally scabs, vesicular fluid, or cells from the base of a lesion. […] PCR is also useful for confirming breakthrough varicella. […] Positive serologic test for varicella-zoster immunoglobulin M (IgM) antibody when a varicella-like rash is present.

• #1 Chickenpox and Shingles Tests: MedlinePlus Medical TestLock

  https://medlineplus.gov/lab-tests/chickenpox-and-shingles-tests/

  Chickenpox and shingles tests check to see if you are or have ever been infected with the varicella zoster virus (VZV). […] Testing for VZV involves checking for VZV in a blood, fluid, or tissue sample. […] Health care providers can usually diagnose chickenpox or shingles with a visual examination. But in some cases, your provider may also order a chickenpox or shingles test to confirm the diagnosis. […] You may need a chickenpox or shingles test if you are at higher risk of complications, are not immune to VZV, and/or have symptoms of infection. […] You will need to provide a sample of blood from your vein or from the fluid in one of your blisters. Blood tests check for antibodies to the VZV. Blister tests check for the virus itself. […] If you have symptoms and your test results show VZV antibodies or the virus itself, it’s likely you have chickenpox or shingles. Your diagnosis of either chickenpox or shingles will depend on your age and specific symptoms. […] The best way to prevent chickenpox is to get the chickenpox vaccine.

• #1 Varicella Zoster Virus Antibody IgG | Quest Diagnostics

  https://www.questdiagnostics.com/healthcare-professionals/clinical-education-center/faq/faq117v1

  VZV IgG testing is useful for the determination of an individuals immune status and/or to aid in the diagnosis of varicella zoster infection. […] A positive VZV IgG result indicates the presence of antibodies to varicella zoster virus. […] The test cannot distinguish between past infection and current infection though, so a positive result could indicate active infection and not immunity. […] If active infection is not suspected based on the patients history, clinical presentation, and other laboratory results, then a positive IgG result is likely due to past infection. […] In such a case, the patient is presumed to be immune to varicella zoster virus. […] Vaccinated individuals generally have a lower level of VZV antibodies than do patients with a history of infection. […] This assay can readily detect antibodies from a past infection, but it might not be able to detect antibodies in all vaccinated people.

• #1 Varicella-Zoster Virus – VZV | Choose the Right Test

  https://arupconsult.com/content/varicella-zoster-virus

  Laboratory confirmation of VZV is increasingly important in routine clinical practice. […] The CDC criteria for VZV diagnosis includes positive identification of VZV by polymerase chain reaction (PCR) testing, direct fluorescent antibody (DFA) staining, culture, or serology. […] If clinical features alone are not confirmatory, especially in patients who have received one or both of the CDC-recommended varicella vaccination doses, laboratory testing is recommended to confirm diagnosis. […] If clinical features alone are not confirmatory, especially in patients who have received the recommended vaccination for shingles and in people with suppressed immune systems, laboratory testing is recommended to confirm diagnosis. […] Laboratory testing may also be appropriate to investigate outbreaks, unusual cases, or severe cases involving hospitalization or death.

• #1 Chickenpox Workup: Approach Considerations, Polymerase chain reaction (PCR), Tzanck Smear

  https://emedicine.medscape.com/article/1131785-workup

  Diagnostic specimens typically are obtained by scraping the base of the lesion and should be transported to the laboratory in appropriate viral transport media. Alternative specimens such as nasopharyngeal secretions, saliva, urine, bronchial washings, and cerebrospinal fluid are generally less ideal for VZV detection, often leading to suboptimal samples and a higher likelihood of false-negative results. […] Histologic examination of skin lesions provides limited differentiation between VZV and HSV. However, specific histologic features such as leukocytoclastic vasculitis and hemorrhage may suggest VZV. Immunohistochemistry and direct fluorescent antibody (DFA) testing can further aid in differentiating between these infections. Other methods like DFA and additional viral cultures generally are less recommended due to their lower sensitivity compared to PCR.

• #1 Varicella-Zoster Virus Test: Key to Diagnosing Chickenpox & Shingles – The Kingsley Clinic

  https://thekingsleyclinic.com/resources/varicella-zoster-virus-test-key-to-diagnosing-chickenpox-shingles/

  Varicella-zoster virus serology is a blood test that detects specific antibodies produced by the immune system in response to VZV. […] This test plays a key role in diagnosing infections, assessing immunity, and guiding treatment decisions. […] The VZV IgM test detects recent or active infections. […] A positive IgM result suggests an active VZV infection, such as chickenpox or shingles. […] Varicella-zoster virus serology is a vital tool in managing chickenpox and shingles. […] Its importance lies in its ability to provide critical information about your immune status, guide treatment decisions, and help prevent complications. […] In cases of suspected shingles, the test can confirm a diagnosis by detecting VZV IgM antibodies. […] The VZV IgM test detects recent or active chickenpox infections, as IgM antibodies are produced early in the infection.

• #1 Varicella – Serology | Public Health Ontario

  https://www.publichealthontario.ca/en/Laboratory-Services/Test-Information-Index/Varicella-Serology

  Serology for Varicella Zoster (IgG) may be indicated to determine immune status following a natural infection or post-vaccination and assess infants suspected of having congenital varicella syndrome. […] Diagnosis of symptomatic patients requires additional samples for testing by PCR. […] Varicella IgG testing will be performed on all requests for Varicella immunity serology. […] Varicella IgG and IgM testing will only be performed on diagnostic requests when clinical information is provided on the General Test Requisition Form. […] The Varicella IgG and IgM tests are performed using chemiluminescence immunoassay technology to qualitatively determine specific IgG and IgM antibodies to the Varicella virus in human serum. […] Following a primary infection, both IgG and IgM antibodies develop within 3-7 days after rash onset. Both antibodies then increase reaching a plateau 2-3 weeks later. […] Varicella IgG test results are reported qualitatively together with an interpretation of the patients immune status based on the level of Varicella IgG detected.

• #1 Chickenpox | Interpreting Laboratory Tests | Varicella | CDC

  http://medbox.iiab.me/modules/en-cdc/www.cdc.gov/chickenpox/hcp/lab-tests.html

  Varicella used to be very common in the United States before varicella vaccine became available. […] However, clinical diagnosis is becoming more challenging because fewer people get varicella and varicella in vaccinated people is often mild and atypical in presentation. […] Therefore, laboratory confirmation of varicella is becoming increasingly important in routine clinical practice. […] Laboratory testing is also recommended to confirm varicella as the cause of outbreaks, establish varicella as a cause of death, and determine susceptibility to varicella. […] The most sensitive method for confirming a diagnosis of varicella is the use of PCR to detect VZV in skin lesions. […] IgM testing is considerably less sensitive than PCR testing of skin lesions. […] A positive IgM ELISA result, although suggestive of a primary infection, does not exclude re-infection or reactivation of latent VZV.

• #1 Laboratory Testing for Varicella-Zoster Virus (VZV) | Chickenpox (Varicella) | CDC

  https://www.cdc.gov/chickenpox/php/laboratories/index.html

  Four-fold or greater rise in serum varicella immunoglobulin G (IgG) antibody titer by any standard serologic assay between acute and convalescent sera. […] For both unvaccinated and vaccinated people, PCR is the most reliable method for confirming a VZV infection. […] Serologic methods have limited use for laboratory confirmation of herpes zoster and should only be used when suitable specimens for PCR testing are not available. […] A positive IgG ELISA result indicates that a person has antibodies to VZV from past varicella disease or vaccination. […] While many commercial VZV IgG ELISAs perform well enough to detect seroconversion for infection by wild-type viruses, the performance specifications (specificity and sensitivity) of these methods vary widely.

• #1 Chickenpox Workup: Approach Considerations, Polymerase chain reaction (PCR), Tzanck Smear

  https://emedicine.medscape.com/article/1131785-workup

  Chickenpox typically is suspected in patients who present with its distinctive rash, which is commonly used for clinical diagnosis. However, this rash also may resemble those associated with other viral dermatoses, necessitating laboratory confirmation in uncertain cases. […] For definitive diagnosis, several laboratory techniques are available: Immunofluorescence identifies viral antigens in lesion samples. Polymerase chain reaction (PCR) is highly recommended for its sensitivity in detecting viral DNA. Serologic assay tests measure IgM antibodies specific to varicella-zoster virus (VZV) or demonstrate seroconversion from negative to positive VZV antibody titers, indicating an acute infection. Tzanck smear is useful for visualizing cellular changes associated with herpes virus infections but does not differentiate between VZV and HSV. Viral culture, although definitive, is less sensitive than PCR and has a longer turnaround time.

• #1 Varicella-Zoster Virus (Chickenpox) – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK448191/

  Chickenpox is diagnosed based on the presenting symptoms and confirmed by polymerase chain reaction testing of the blister fluid or scabs. […] Diagnosis is typically clinical, though laboratory tests may confirm cases or identify complications. […] The diagnosis of varicella infection is primarily based on the signs and symptoms. Confirmation is made by examination of the fluid within the vesicles, scraping of lesions that have not crusted, or by blood for evidence of an acute immunologic response. Polymerase chain reaction (PCR) has the highest yield and can be used for nonskin samples such as bronchoalveolar lavage and cerebrospinal fluid. […] Direct fluorescent antibody testing has largely replaced the Tzanck test. […] Blood tests identify a response to acute infection (IgM), previous infection, and subsequent immunity (IgG).

• #1 Chickenpox – Wikipedia

  https://en.wikipedia.org/wiki/Chickenpox

  The diagnosis of chickenpox is primarily based on the signs and symptoms, with typical early symptoms followed by a characteristic rash. Confirmation of the diagnosis is by examination of the fluid within the vesicles of the rash, or by testing blood for evidence of an acute immunologic response. […] Vesicular fluid can be examined with a Tzanck smear, or by testing for direct fluorescent antibody. The fluid can also be „cultured”, whereby attempts are made to grow the virus from a fluid sample. Blood tests can be used to identify a response to acute infection (IgM) or previous infection and subsequent immunity (IgG). […] Prenatal diagnosis of fetal varicella infection can be performed using ultrasound, though a delay of 5 weeks following primary maternal infection is advised. A PCR (DNA) test of the mother’s amniotic fluid can also be performed, though the risk of spontaneous abortion due to the amniocentesis procedure is higher than the risk of the baby’s developing fetal varicella syndrome.

• #1 Diagnosis and Management of Varicella Infection in Pregnancy

  http://www.perinatology.com/exposures/Infection/Varicella/Varicella.htm

  Varicella usually causes a typical skin eruption. The lesions begin as raised red papules that progress quickly to clear vesicles. The vesicles then become cloudy pustules and, subsequently, dry to form crusted lesions. The lesions usually begin on the face and trunk and spread centripetally to the extremities. The lesions are intensely pruritic and occur in crops. […] The diagnosis of acute varicella infection can usually be established on the basis of clinical findings alone. However, in problematic cases, varicella-zoster serology can be performed to confirm the diagnosis. Acutely infected patients typically have positive IgM antibody and negative IgG antibody. […] As noted previously, the frequency of congenital malformations due to varicella infection, even in the first half of pregnancy, is = 2%. The single best test for diagnosis of fetal injury is ultrasound examination. The principal ultrasound findings suggestive of congenital varicella infection are intrauterine growth restriction, microcephaly, ventriculomegaly, the presence of echogenic foci in the fetal liver, and circular scarring and deformities of the limbs.

• #1 Chickenpox Differential Diagnoses

  https://emedicine.medscape.com/article/1131785-differential

  Diagnostic considerations in cases of suspected chickenpox include viral exanthems, pityriasis lichenoides et varioliformis acuta, disseminated herpes simplex virus infection, atypical herpes zoster, rickettsial disease, and neonatal syphilis. […] When delineating chickenpox and Mpox, the latter may display lymphadenopathy as a distinguishing feature. […] All of the differential diagnoses listed are active considerations, with the exception of smallpox, which would be a concern in the event of biologic warfare. […] CDC. Laboratory Testing for Varicella-Zoster Virus (VZV). US Centers for Disease Control and Prevention. Available at https://www.cdc.gov/chickenpox/php/laboratories/index.html. May 10, 2024; Accessed: March 13, 2025.

• #1 Chickenpox Workup: Approach Considerations, Polymerase chain reaction (PCR), Tzanck Smear

  https://emedicine.medscape.com/article/1131785-workup

  The study concluded that PCR is a more reliable and effective method for diagnosing both HSV and VZV infections compared to traditional viral cultures, especially for VZV. This suggests that PCR should be considered a preferred diagnostic tool in clinical settings for its higher sensitivity and specificity. […] PCR testing is highly sensitive for detecting varicella-zoster virus (VZV) DNA and is considered the gold standard for laboratory confirmation. Optimal specimens for PCR include vesicular lesions or scabs. […] Serologic testing is utilized to identify VZV-specific antibodies (IgM and IgG) and can indicate acute infection through seroconversion. Various assays are employed, including complement fixation, enzyme immunoassay, fluorescent antibody to membrane assay, indirect fluorescent antibody, and latex agglutination test.

• #1 Varicella-Zoster Virus – VZV | Choose the Right Test

  https://arupconsult.com/content/varicella-zoster-virus

  PCR testing is the most rapid and sensitive method for confirming a diagnosis of varicella or herpes zoster. […] PCR is the preferred test for VZV infection. […] Serology has limited utility for laboratory diagnosis of VZV and should only be used when suitable specimens for PCR testing are not available. […] Viral culture of VZV is not recommended for initial diagnosis because its slow turnaround time may adversely impact clinical management.

• #1 Pri-Med | Spot On: Evolving Strategies for…

  https://www.pri-med.com/online-cme-ce/podcast/frankly-speaking-cme-390

  In 1995, the US launched a varicella vaccination program, leading to a significant drop in cases. […] However, breakthrough infections still occur, and clinical diagnosis has become less reliable as the virus has evolved. […] Join us to hear current recommendations for what to consider in the differential diagnosis and how emerging evidence may impact public health and your practice. […] Summarize why varicella has breakthrough cases, even though incidence has declined with vaccination, and needs to be considered in the differential diagnosis when appropriate. […] Describe how the clinical diagnosis of varicella is often missed, especially in vaccinated individuals, making lab confirmation necessary to support patient and public health and gather data on vaccination efficacy.

• #2 Chickenpox | Interpreting Laboratory Tests | Varicella | CDC

  http://medbox.iiab.me/modules/en-cdc/www.cdc.gov/chickenpox/hcp/lab-tests.html

  Varicella used to be very common in the United States before varicella vaccine became available. […] However, clinical diagnosis is becoming more challenging because fewer people get varicella and varicella in vaccinated people is often mild and atypical in presentation. […] Therefore, laboratory confirmation of varicella is becoming increasingly important in routine clinical practice. […] Laboratory testing is also recommended to confirm varicella as the cause of outbreaks, establish varicella as a cause of death, and determine susceptibility to varicella. […] The most sensitive method for confirming a diagnosis of varicella is the use of PCR to detect VZV in skin lesions. […] IgM testing is considerably less sensitive than PCR testing of skin lesions. […] A positive IgM ELISA result, although suggestive of a primary infection, does not exclude re-infection or reactivation of latent VZV.

• #2 Chickenpox: Causes, Symptoms, Treatment & Prevention

  https://my.clevelandclinic.org/health/diseases/4017-chickenpox

  Signs of chickenpox are easy to see. Healthcare providers often can look at your childs skin and know if they have chickenpox. […] Chickenpox symptoms are easy to see. Healthcare providers often can look at your childs skin and know if they have chickenpox. Symptoms of chickenpox usually happen in the following order: […] How is chickenpox diagnosed? […] Chickenpox is contagious until all bumps on your body are scabs. If you have any fluid-filled blisters that havent broken or scabbed over, youre still able to spread the virus. […] Chickenpox usually goes away after 10 to 14 days.

• #2 Chickenpox Workup: Approach Considerations, Polymerase chain reaction (PCR), Tzanck Smear

  https://emedicine.medscape.com/article/1131785-workup

  The study concluded that PCR is a more reliable and effective method for diagnosing both HSV and VZV infections compared to traditional viral cultures, especially for VZV. This suggests that PCR should be considered a preferred diagnostic tool in clinical settings for its higher sensitivity and specificity. […] PCR testing is highly sensitive for detecting varicella-zoster virus (VZV) DNA and is considered the gold standard for laboratory confirmation. Optimal specimens for PCR include vesicular lesions or scabs. […] Serologic testing is utilized to identify VZV-specific antibodies (IgM and IgG) and can indicate acute infection through seroconversion. Various assays are employed, including complement fixation, enzyme immunoassay, fluorescent antibody to membrane assay, indirect fluorescent antibody, and latex agglutination test.

• #3 Varicella-Zoster Virus – VZV | Choose the Right Test

  https://arupconsult.com/content/varicella-zoster-virus

  Laboratory confirmation of VZV is increasingly important in routine clinical practice. […] The CDC criteria for VZV diagnosis includes positive identification of VZV by polymerase chain reaction (PCR) testing, direct fluorescent antibody (DFA) staining, culture, or serology. […] If clinical features alone are not confirmatory, especially in patients who have received one or both of the CDC-recommended varicella vaccination doses, laboratory testing is recommended to confirm diagnosis. […] If clinical features alone are not confirmatory, especially in patients who have received the recommended vaccination for shingles and in people with suppressed immune systems, laboratory testing is recommended to confirm diagnosis. […] Laboratory testing may also be appropriate to investigate outbreaks, unusual cases, or severe cases involving hospitalization or death.

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