Denga – Diagnostyka i diagnoza

Denga
Diagnostyka i diagnoza

Denga jest wirusową chorobą przenoszoną przez komary, której diagnostyka laboratoryjna obejmuje wykrywanie antygenu NS1, RNA wirusa (RT-PCR), izolację wirusa oraz ocenę przeciwciał IgM i IgG. Antygen NS1 jest wykrywalny w surowicy do 7 dni od wystąpienia objawów, a testy RT-PCR umożliwiają identyfikację serotypu wirusa w ciągu pierwszych 4-5 dni choroby. Przeciwciała IgM pojawiają się od 4-5 dnia i utrzymują do 12 tygodni, natomiast IgG rozwijają się wolniej i utrzymują się latami. Diagnostyka powinna uwzględniać czas trwania objawów, a w przypadku podejrzenia dengi zaleca się wykonanie testów NS1 ELISA i IgM lub RT-PCR i IgM. Wyniki testów należy interpretować z uwzględnieniem możliwych reakcji krzyżowych z innymi flawiwirusami oraz konieczności powtórzenia badań serologicznych po 7 dniach w przypadku wątpliwych wyników.

Diagnostyka Dengi

Testy diagnostyczne dengi
Metody bezpośrednie wykrywania wirusa
Metody serologiczne
Interpretacja wyników testów
Ograniczenia testów diagnostycznych
Badania pomocnicze

Badania obrazowe w diagnostyce dengi
Szybkie testy diagnostyczne (RDT)
Znaczenie diagnostyki laboratoryjnej
Zalecenia diagnostyczne w różnych fazach choroby

Wczesna faza ostra (0-7 dni od wystąpienia objawów)
Późna faza ostra (>7 dni od wystąpienia objawów)

Znaczenie dla nadzoru epidemiologicznego
Podsumowanie metod diagnostycznych
Wskazówki praktyczne dla lekarzy
Przyszłość diagnostyki dengi

Kolejne rozdziały

Diagnostyka Dengi

Denga (Dengue fever) to choroba wirusowa przenoszona przez komary, będąca istotnym problemem zdrowia publicznego na całym świecie. Skuteczna i dokładna diagnostyka dengi ma kluczowe znaczenie dla właściwej opieki klinicznej, w tym wczesnego wykrywania ciężkich przypadków, potwierdzenia przypadków i diagnostyki różnicowej z innymi chorobami zakaźnymi¹. Diagnostyka laboratoryjna dengi może obejmować wykrywanie wirusa, kwasu nukleinowego wirusa, antygenów lub przeciwciał, bądź kombinację tych technik².

Testy diagnostyczne dengi

Lekarze powinni rozważyć możliwość zakażenia wirusem dengi u pacjentów z gorączką, którzy mieszkają lub ostatnio podróżowali do obszarów zagrożonych dengą. Oprócz gorączki, typowe objawy dengi obejmują silny ból głowy, ból zagałkowy, bóle mięśni i stawów, wysypkę plamistą lub plamisto-grudkową³. Diagnostykę często rozpoczyna się od dokładnego wywiadu medycznego i dotyczącego podróży. Należy szczegółowo opisać międzynarodowe podróże, w tym kraje odwiedzone i daty, a także ewentualny kontakt z komarami⁴.

W przypadku podejrzenia dengi zaleca się następujące testy diagnostyczne:

Metody bezpośrednie wykrywania wirusa

Wykrywanie antygenu NS1: Testy wykrywające niestrukturalny antygen 1 (NS1) w surowicy mogą zapewnić wczesną diagnozę u pacjentów z gorączką. NS1 jest wykrywalny w ostrej fazie zakażenia wirusem dengi, zwykle w okresie gorączkowym lub do 7 dni po wystąpieniu objawów⁵⁶. Testy te mogą być równie czułe jak testy molekularne w tym okresie⁷.
Testy molekularne (NAAT): Metody amplifikacji kwasu nukleinowego, takie jak RT-PCR (reakcja łańcuchowa polimerazy z odwrotną transkryptazą), mogą wykrywać RNA wirusa dengi we krwi, surowicy i osoczu. Większość tych testów identyfikuje serotyp zakaźnego wirusa dengi. Pozytywny wynik testu NAAT nie wymaga dalszych testów potwierdzających⁸. RNA wirusa można wykryć w ciągu pierwszych 4-5 dni od wystąpienia objawów⁹.
Izolacja wirusa: Uważana za złoty standard w diagnostyce dengi, ale rzadziej stosowana w rutynowej praktyce klinicznej ze względu na czas trwania i złożoność. Wirus można izolować poprzez inokulację próbek do komarów, hodowli komórkowych lub śródmózgowo u myszy¹⁰.

Metody serologiczne

Testy na przeciwciała IgM: Zalecane jako podstawowy test po 7 dniu od wystąpienia objawów¹¹. Przeciwciała IgM są wykrywalne począwszy od 4-5 dni po wystąpieniu objawów i utrzymują się przez około 12 tygodni¹². Pacjenci z pozytywnym wynikiem testu IgM w pojedynczej próbce są klasyfikowani jako mający domniemane, niedawne zakażenie wirusem dengi¹³.
Testy na przeciwciała IgG: Przeciwciała IgG są produkowane wolniej w odpowiedzi na zakażenie. Zazwyczaj ich poziom wzrasta przy ostrej infekcji, stabilizuje się, a następnie utrzymuje się długoterminowo. Osoby, które były narażone na kontakt z wirusem przed obecnym zakażeniem, utrzymują pewien poziom przeciwciał IgG we krwi¹⁴.
Test neutralizacji redukcji płytek (PRNT): Stosowany do bardziej precyzyjnego określenia przyczyny zakażenia u pacjentów z dodatnim wynikiem IgM, dla których ważna jest klinicznie lub epidemiologicznie określona diagnoza (np. w celu wykluczenia innych flawiwirusów, takich jak Zika lub żółta gorączka)¹⁵.

Interpretacja wyników testów

Dla ostrej diagnozy dengi, lekarze powinni zlecić testy NS1 ELISA i IgM lub testy NAAT i IgM¹⁶. Preferowaną próbką do testów na dengę jest surowica¹⁷.

Pozytywny wynik NS1 lub RT-PCR: Pacjenci z pozytywnym wynikiem testu NAAT (np. RT-PCR) lub testu NS1 ELISA mają potwierdzone ostre zakażenie wirusem dengi¹⁸.
Negatywny wynik NS1 lub RT-PCR: Negatywny wynik testu RT-PCR lub NS1 ELISA nie wyklucza zakażenia¹⁹.
Pozytywny wynik IgM: Pacjenci, którzy mają przeciwciała IgM przeciwko wirusowi dengi w pojedynczej próbce, są klasyfikowani jako mający domniemane, niedawne zakażenie wirusem dengi²⁰.
Negatywny wynik IgM: Pacjenci z negatywnym wynikiem IgM między 0-7 dniem choroby i brakiem lub negatywnym wynikiem NAAT lub NS1 są uważani za przypadki niepotwierdzone. W takich przypadkach należy pobrać drugą próbkę po 7 dniu od wystąpienia objawów w celu dodatkowych testów serologicznych²¹.
Serokonwersja: Obserwuje się ją, gdy próbka ostra (zwykle pobrana w pierwszym dniu choroby) i próbka rekonwalescencyjna (pobrana po 7 dniach) są badane na obecność IgM. Jeśli wyniki testów zmieniają się z negatywnych na pozytywne, pacjent jest diagnozowany jako mający aktualne zakażenie dengą²².

Ograniczenia testów diagnostycznych

Testy serologiczne na dengę są bardziej dostępne w krajach endemicznych niż testy wirusologiczne²³. Jednak wiążą się z pewnymi ograniczeniami:

Reakcje krzyżowe: Reaktywność krzyżowa jest ograniczeniem testów serologicznych dengi i występuje, gdy przeciwciała przeciwko innym flawiwirusom reagują w teście IgM dengi²⁴. Z powodu reakcji krzyżowych z innymi flawiwirusami i możliwej niespecyficznej reaktywności, wyniki IgM i IgG mogą być trudne do interpretacji²⁵.
Czas pobierania próbek: Dla serologii czas pobierania próbek jest bardziej elastyczny niż w przypadku izolacji wirusa lub wykrywania RNA, ponieważ odpowiedź przeciwciał można zmierzyć, porównując próbkę pobraną w ostrej fazie choroby z próbkami pobranymi tygodnie lub miesiące później²⁶.
Wcześniejsze zakażenia: Głównym ograniczeniem stosowania testów serologicznych ELISA w regionach endemicznych dengi jest utrzymywanie się przeciwciał z poprzednich zakażeń²⁷.

Badania pomocnicze

Oprócz testów specyficznych dla dengi, w diagnostyce pomocne są rutynowe badania hematologiczne:

Morfologia krwi: Może wykazać leukopenię (obniżoną liczbę białych krwinek) i trombocytopenię (obniżoną liczbę płytek krwi), które są typowymi zmianami w przebiegu dengi²⁸.
Hematokryt: Zagęszczenie krwi, szacowane jako wzrost hematokrytu o 20% lub więcej w porównaniu z wartościami w okresie rekonwalescencji, sugeruje hipowolemia spowodowaną przepuszczalnością naczyń i wyciekiem osocza²⁹.
Poziom płytek krwi: Spadek liczby płytek krwi poniżej 100 000 na μL może być obserwowany w gorączce denga, ale jest stałą cechą dengi krwotocznej³⁰.

Badania obrazowe w diagnostyce dengi

W ciężkich przypadkach dengi mogą być konieczne badania obrazowe, które obejmują:

Radiografia klatki piersiowej: Do wykrywania płynu w klatce piersiowej³¹.
Tomografia komputerowa głowy bez kontrastu: W celu wykrycia krwawienia wewnątrzczaszkowego lub obrzęku mózgu spowodowanego ciężką dengą³².
Ultrasonografia: Do wykrywania płynu w jamach klatki piersiowej i brzusznej, wysięku osierdziowego i pogrubienia ściany pęcherzyka żółciowego u pacjentów z ciężką dengą³³.

Szybkie testy diagnostyczne (RDT)

Szybkie testy diagnostyczne są coraz częściej stosowane ze względu na łatwość użycia w porównaniu z technikami takimi jak hodowla komórkowa lub wykrywanie RNA³⁴. Obejmują one:

Szybkie testy NS1: Umożliwiają szybką i łatwą metodę stosowania w miejscu opieki lub przy łóżku pacjenta i istnieją w różnych formatach, w tym aglutynacja cząstek i paski immunochromatograficzne przepływu bocznego, z kasetami z tworzywa sztucznego lub bez nich³⁵.
Szybkie testy IgM/IgG: Testy łączące wykrywanie antygenu i przeciwciał mogą osiągać wartości czułości i swoistości bliskie 90%, co czyni je dobrą opcją dla rozszerzonego nadzoru³⁶.

Znaczenie diagnostyki laboratoryjnej

Znaczenie laboratoryjnego potwierdzenia zakażenia wirusem dengi jest kluczowe³⁷. Chociaż w praktyce diagnoza często opiera się wyłącznie na objawach klinicznych, denga w fazie gorączkowej nie może być klinicznie odróżniona od innych chorób przenoszonych przez wektory, takich jak malaria, chikungunya czy gorączka Zika³⁸.

Śmiertelność z powodu dengi można zmniejszyć prawie do zera poprzez wdrożenie terminowego, odpowiedniego postępowania klinicznego, które obejmuje wczesną diagnostykę kliniczną i laboratoryjną, doustne i dożylne nawadnianie, szkolenie personelu i reorganizację usług zdrowotnych³⁹.

Zalecenia diagnostyczne w różnych fazach choroby

W oparciu o czas trwania objawów, zaleca się następujące podejście diagnostyczne:

Wczesna faza ostra (0-7 dni od wystąpienia objawów)

Wykrywanie antygenu NS1 (test ELISA lub szybki test)
Testy molekularne (RT-PCR) do wykrywania RNA wirusa
Po dniu 4-5: testy na przeciwciała IgM

Późna faza ostra (>7 dni od wystąpienia objawów)

Testy serologiczne na przeciwciała IgM i IgG
Porównanie próbek ostrej i rekonwalescencyjnej w celu wykazania serokonwersji lub czterokrotnego lub większego wzrostu miana przeciwciał

Znaczenie dla nadzoru epidemiologicznego

Skuteczny nadzór epidemiologiczny nad gorączką denga musi obejmować możliwość rutynowego laboratoryjnego potwierdzania i monitorowania krążących serotypów⁴⁰. Nadzór laboratoryjny jest niezbędny, aby można było przeprowadzić diagnostykę różnicową między gorączką denga a innymi ostrymi chorobami gorączkowymi ze względu na podobieństwa kliniczne⁴¹.

W przypadku podejrzenia wybuchu epidemii jednym z priorytetów jest identyfikacja czynnika przyczynowego, aby można było podjąć odpowiednie środki zdrowia publicznego, a lekarze mogli rozpocząć odpowiednie leczenie ostrej choroby⁴².

Podsumowanie metod diagnostycznych

Metoda diagnostyczna	Czas wykrywalności	Zalety	Ograniczenia
Wykrywanie antygenu NS1	Od 0 do 7 dni od wystąpienia objawów	Szybka, wczesna diagnoza; nie wymaga sprzętu specjalistycznego	Nie identyfikuje serotypu; czułość zależy od serotypu i pierwotnego/wtórnego zakażenia
RT-PCR (NAAT)	Od 0 do 5 dni od wystąpienia objawów	Wysoka czułość i swoistość; identyfikacja serotypu	Wymaga specjalistycznego sprzętu i przeszkolonego personelu; wyższy koszt
Izolacja wirusa	Od 0 do 5 dni od wystąpienia objawów	Złoty standard; wysoka swoistość	Czasochłonna; wymaga specjalistycznych laboratoriów; nieodpowiednia dla rutynowej diagnostyki
Przeciwciała IgM	Od 4-5 dni do 12 tygodni od wystąpienia objawów	Szerzej dostępna; łatwiejsza do wykonania	Możliwe reakcje krzyżowe z innymi flawiwirusami; mniej czuła we wtórnych zakażeniach
Przeciwciała IgG	Od około 10 dni; utrzymują się latami	Użyteczne do wykrywania wcześniejszych zakażeń	Nie nadaje się do diagnozy ostrego zakażenia bez próbek sparowanych
PRNT	Późna faza i faza rekonwalescencji	Wysoka swoistość; pomaga w różnicowaniu flawiwirusów	Wymagające technicznie; czasochłonne; dostępne głównie w laboratoriach referencyjnych

Wskazówki praktyczne dla lekarzy

Wszyscy pacjenci z klinicznym podejrzeniem dengi powinni otrzymać odpowiednie leczenie bez oczekiwania na wyniki testów diagnostycznych⁴³. Próbki kliniczne można kierować do większości stanowych departamentów zdrowia lub do laboratoriów komercyjnych, które oferują diagnostykę dengi⁴⁴.

Dla lekarzy kluczowe jest zrozumienie mocnych stron i ograniczeń różnych testów diagnostycznych, aby wybrać najbardziej odpowiednie badania dla każdego pacjenta w zależności od czasu trwania objawów, dostępności testów i kontekstu klinicznego.

Przyszłość diagnostyki dengi

Rozwój technik diagnostycznych, które są czułe, swoiste, szybkie i przystępne cenowo, pozostaje ważnym obszarem badań. Idealna metoda diagnostyczna powinna umożliwiać wczesną i szybką diagnozę, być przystępna cenowo dla różnych systemów opieki zdrowotnej, łatwa w wykonaniu i charakteryzować się solidną wydajnością⁴⁵.

Postępy w technologii biosensorów i metod molekularnych mogą w przyszłości poprawić diagnostykę dengi, oferując wyższą czułość, krótszy czas do uzyskania wyniku i możliwość stosowania w miejscach o ograniczonych zasobach⁴⁶.

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Materiały źródłowe

#1 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#2
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management
Laboratory confirmation of dengue virus infection is important. […] Diagnosis may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these entities. […] Laboratory tests using NS1 (non-structural protein 1) antigen can provide early diagnosis in febrile patients. […] During the acute stage of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. […] At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] Serological assays to detect specific immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies to dengue virus are widely available and can provide an alternative to virus isolation or polymerase chain reaction to support the diagnosis of dengue fever.
#3 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
Clinicians should consider dengue in patients with fever, who live in or recently traveled to areas with risk of dengue. In addition to fever, common dengue symptoms include severe headache, retro-orbital pain, myalgia and arthralgia, macular or maculopapular rash. […] For acute dengue diagnosis, clinicians should order NS1 ELISA and IgM tests or NAAT and IgM tests. […] A serum sample is preferred for dengue testing. […] Dengue virus RNA can be detected with NAAT in blood, serum, and plasma. Most of these tests identify the infecting dengue virus serotype. A positive NAAT test does not require further confirmatory testing. […] The presence of the dengue virus non-structural protein 1 (NS1) in blood (serum) during the first 7 days of illness is indicative of a current or recent dengue virus infection.
#4 Dengue fever – Diagnosis and treatment – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/dengue-fever/diagnosis-treatment/drc-20353084
Diagnosing dengue fever can be difficult because its signs and symptoms can be easily confused with those of other diseases such as chikungunya, Zika virus, malaria and typhoid fever. […] Your doctor will likely ask about your medical and travel history. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with mosquitoes. […] Your doctor may also draw a sample of blood to be tested in a lab for evidence of infection with one of the dengue viruses. […] For dengue fever, some basic questions to ask your doctor include: What kinds of tests do I need? […] What to expect from your doctor: Be prepared to answer questions from your doctor, such as: Where have you traveled in the past month? […] Were you bitten by mosquitoes while traveling?
#5
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management
Laboratory confirmation of dengue virus infection is important. […] Diagnosis may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these entities. […] Laboratory tests using NS1 (non-structural protein 1) antigen can provide early diagnosis in febrile patients. […] During the acute stage of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. […] At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] Serological assays to detect specific immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies to dengue virus are widely available and can provide an alternative to virus isolation or polymerase chain reaction to support the diagnosis of dengue fever.
#6 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
Clinicians should consider dengue in patients with fever, who live in or recently traveled to areas with risk of dengue. In addition to fever, common dengue symptoms include severe headache, retro-orbital pain, myalgia and arthralgia, macular or maculopapular rash. […] For acute dengue diagnosis, clinicians should order NS1 ELISA and IgM tests or NAAT and IgM tests. […] A serum sample is preferred for dengue testing. […] Dengue virus RNA can be detected with NAAT in blood, serum, and plasma. Most of these tests identify the infecting dengue virus serotype. A positive NAAT test does not require further confirmatory testing. […] The presence of the dengue virus non-structural protein 1 (NS1) in blood (serum) during the first 7 days of illness is indicative of a current or recent dengue virus infection.
#7
https://www.mountelizabeth.com.sg/conditions-diseases/dengue-fever/diagnosis-treatment
Testing for dengue fever is done to determine whether a person with signs and symptoms, and recent potential exposure, has been infected with the dengue virus. The infection is difficult to diagnose without laboratory tests because symptoms may initially resemble those of other diseases. […] If the clinical suspicion of dengue fever is high, blood tests would be undertaken. These include a full blood count and may include the following: […] Dengue virus antigen detection (NS1): This detects the NS1 protein of the dengue virus, which is secreted into the blood during dengue infection. NS1 is detectable during the acute phase of dengue virus infections, usually during the febrile period or up to first 7 days of symptoms. It can be as sensitive as molecular tests during this period. […] Antibody tests: This is a dengue test for IgM antibodies. Dengue virus-specific IgM and neutralising antibodies typically develop toward the end of the first week of illness. They are generally positive starting 4 5 days after the onset of symptoms, and continues for approximately 12 weeks afterwards, but may persist longer.
#8 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
Clinicians should consider dengue in patients with fever, who live in or recently traveled to areas with risk of dengue. In addition to fever, common dengue symptoms include severe headache, retro-orbital pain, myalgia and arthralgia, macular or maculopapular rash. […] For acute dengue diagnosis, clinicians should order NS1 ELISA and IgM tests or NAAT and IgM tests. […] A serum sample is preferred for dengue testing. […] Dengue virus RNA can be detected with NAAT in blood, serum, and plasma. Most of these tests identify the infecting dengue virus serotype. A positive NAAT test does not require further confirmatory testing. […] The presence of the dengue virus non-structural protein 1 (NS1) in blood (serum) during the first 7 days of illness is indicative of a current or recent dengue virus infection.
#9
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management/enhancing-dengue-diagnosis-and-case-management
Laboratory confirmation of dengue virus infection is important. Although in practice diagnosis is often made by clinical signs and symptoms only, dengue in its febrile phase cannot be clinically differentiated from other vector-borne viral and parasitic diseases, such as malaria, chikungunya and Zika fever. […] Diagnosis may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these entities. Laboratory tests using NS1 (non-structural protein 1) antigen can provide early diagnosis in febrile patients. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 4-5 days. During the acute stage of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. Serological assays to detect specific immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies to dengue virus are widely available and can provide an alternative to virus isolation or polymerase chain reaction to support the diagnosis of dengue fever.
#10 Evaluation of diagnostic tests: dengue | Nature Reviews Microbiology
https://www.nature.com/articles/nrmicro2459
Serological tests are more commonly used to diagnose dengue infections because of their ease of use compared to techniques such as cell culture or RNA detection. […] Several rapid diagnostic tests are commercially available and many in-house assays have been developed but the performance characteristics of many of these tests have not been adequately evaluated. […] The purpose of this guide is to establish best practice guidelines for how to design and conduct evaluations of dengue diagnostic tests for the management of acute infections, surveillance and monitoring of interventions. […] The tests that are currently used in the laboratory diagnosis of dengue infections, and their advantages and limitations, are shown in Table 1. […] Dengue virus can be isolated by the inoculation of diagnostic samples into mosquitoes, cell culture (using mosquito cell lines, such as C6/36 and AP61 or mammalian cell lines, such as Vero and LLC-MK2 cells) or intra-cerebral inoculation of suckling mice.
#11 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#12 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
Dengue IgM antibody testing is recommended in combination with nucleic acid amplification tests (NAAT) or NS1 antigen tests during the first 7 days of illness. […] IgM levels are positive starting 45 days after onset of symptoms and continuing for approximately 12 weeks post symptom onset but may persist longer. […] IgM antibody testing can identify dengue infections, but cross-reactivity with other flaviviruses should be considered when interpreting results. […] As the immune system fights the infection, IgM antibodies against dengue virus are detectable starting 45 days after onset of symptoms and are reliably detectable for approximately 12 weeks. […] Combined testing with a nucleic acid amplification test (NAAT) and MAC-ELISA usually provides a diagnostic result during the first 17 days of illness. A convalescent phase specimen is needed to make a diagnosis of dengue virus infection when results are negative on both tests from the acute specimen.
#13 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
IgM antibody detection is not useful for dengue virus serotype determination. […] Positive IgM: Patients with a positive IgM test result in a single sample are classified as presumptive, recent dengue virus infections. […] Negative IgM: Patients with a negative IgM result between days 07 of illness, and absent or negative NAAT or NS1 results, are considered unconfirmed cases. For these cases, a second sample should be obtained after day 7 of symptoms for additional serologic testing. […] Patients with negative IgM results after 7 days of symptoms, and absent or negative NAAT or NS1 (dengue virus antigen detection), are classified as negative for recent infection. […] Patients with a change from negative to positive IgM results in paired samples (first sample collected during the first 7 days of illness, and second sample collected after symptoms subside) are classified as current dengue infections.
#14
https://www.mountelizabeth.com.sg/conditions-diseases/dengue-fever/diagnosis-treatment
Dengue test for IgG antibodies: Antibodies are produced more slowly in response to an infection. Typically, the level rises with an acute infection, stabilises, and then persists long-term. Individuals who have been exposed to the virus prior to the current infection maintain a level of IgG antibodies in the blood.
#15 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
The CDC does not recommend IgG testing on a single specimen for the diagnosis of acute dengue infections. […] PRNT is used to more precisely determine the cause of infection in IgM positive patients for whom a specific diagnosis is clinically or epidemiologically important (e.g., to rule out other flaviviruses such as Zika or yellow fever). […] PRNT performed on a dengue IgM-positive specimen showing neutralizing antibodies to only one dengue virus serotype will confirm recent infection with that serotype. […] A seroconversion from a negative PRNT in an acute sample to a positive PRNT with antibodies to only one dengue virus serotype in a convalescent sample will confirm a recent infection with that serotype. […] A negative PRNT or microneutralization results on a dengue IgM positive sample during acute illness may indicate no detectable neutralizing activity. An IgM positive result remains presumptive in the absence of other confirmatory tests results (PRNT, microneutralization tests, NS1 or NAAT).
#16 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
Clinicians should consider dengue in patients with fever, who live in or recently traveled to areas with risk of dengue. In addition to fever, common dengue symptoms include severe headache, retro-orbital pain, myalgia and arthralgia, macular or maculopapular rash. […] For acute dengue diagnosis, clinicians should order NS1 ELISA and IgM tests or NAAT and IgM tests. […] A serum sample is preferred for dengue testing. […] Dengue virus RNA can be detected with NAAT in blood, serum, and plasma. Most of these tests identify the infecting dengue virus serotype. A positive NAAT test does not require further confirmatory testing. […] The presence of the dengue virus non-structural protein 1 (NS1) in blood (serum) during the first 7 days of illness is indicative of a current or recent dengue virus infection.
#17 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
Clinicians should consider dengue in patients with fever, who live in or recently traveled to areas with risk of dengue. In addition to fever, common dengue symptoms include severe headache, retro-orbital pain, myalgia and arthralgia, macular or maculopapular rash. […] For acute dengue diagnosis, clinicians should order NS1 ELISA and IgM tests or NAAT and IgM tests. […] A serum sample is preferred for dengue testing. […] Dengue virus RNA can be detected with NAAT in blood, serum, and plasma. Most of these tests identify the infecting dengue virus serotype. A positive NAAT test does not require further confirmatory testing. […] The presence of the dengue virus non-structural protein 1 (NS1) in blood (serum) during the first 7 days of illness is indicative of a current or recent dengue virus infection.
#18 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#19 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#20 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#21 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
IgM antibody detection is not useful for dengue virus serotype determination. […] Positive IgM: Patients with a positive IgM test result in a single sample are classified as presumptive, recent dengue virus infections. […] Negative IgM: Patients with a negative IgM result between days 07 of illness, and absent or negative NAAT or NS1 results, are considered unconfirmed cases. For these cases, a second sample should be obtained after day 7 of symptoms for additional serologic testing. […] Patients with negative IgM results after 7 days of symptoms, and absent or negative NAAT or NS1 (dengue virus antigen detection), are classified as negative for recent infection. […] Patients with a change from negative to positive IgM results in paired samples (first sample collected during the first 7 days of illness, and second sample collected after symptoms subside) are classified as current dengue infections.
#22 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
Seroconversion is observed when an acute sample (usually collected during the first day of illness), and a convalescent sample (collected after 7 days), are tested for IgM. If test results change from negative to positive, the patient is diagnosed with current dengue. […] Negative results on both samples are a strong indication the patient was not infected with dengue virus. […] Due to cross-reaction with other flaviviruses and possible nonspecific reactivity, IgM and IgG results may be difficult to interpret. Consequently, presumed positive, indeterminate, and equivocal, IgM antibody test results may be forwarded for confirmation by plaque reduction neutralization testing (PRNT). […] Dengue IgM serologic tests are available as laboratory-developed tests in public health and commercial clinical laboratories.
#23 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#24 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#25 Serologic Tests for Dengue Virus | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/serologic-tests-for-dengue-virus.html
Seroconversion is observed when an acute sample (usually collected during the first day of illness), and a convalescent sample (collected after 7 days), are tested for IgM. If test results change from negative to positive, the patient is diagnosed with current dengue. […] Negative results on both samples are a strong indication the patient was not infected with dengue virus. […] Due to cross-reaction with other flaviviruses and possible nonspecific reactivity, IgM and IgG results may be difficult to interpret. Consequently, presumed positive, indeterminate, and equivocal, IgM antibody test results may be forwarded for confirmation by plaque reduction neutralization testing (PRNT). […] Dengue IgM serologic tests are available as laboratory-developed tests in public health and commercial clinical laboratories.
#26 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#27 A review of dengue diagnostics and implications for surveillance and control
https://pmc.ncbi.nlm.nih.gov/articles/PMC6836713/
Furthermore, diagnostic methods vary in their sensitivity and specificity, meaning that not all reported cases of dengue are equally accurate. […] This review aims to describe the different methods of dengue diagnosis, their practical and diagnostic limitations and the resulting implications for dengue surveillance and control. […] A major limitation in using antibody serology assays in dengue-endemic regions is antibody persistence from previous infections. […] Overall, antibody ELISAs provide a cheap method of testing dengue infection but need to be interpreted with caution in areas of high flavivirus co-transmission/vaccination, particularly if only one sample is available, and thus are most likely to be useful in non-endemic settings. […] The gold standard for determining previous dengue exposure (and vaccine immunogenicity) is the PRNT.
#28 Challenges in the Laboratory Diagnosis and Management of Dengue Infections
https://openmicrobiologyjournal.com/VOLUME/9/PAGE/33/FULLTEXT/
Although the gold standard for laboratory diagnosis of acute dengue virus infection is considered to be isolation and characterization of the virus, however, there are many drawbacks in this procedure. Virus isolation is expensive and it also requires six to ten days to replicate in tissue culture cells. Hence it cannot be recommended for clinical diagnosis case management. The most commonly used method is enzyme immunoassay (ELISA as it is cost-effective, less time consuming and more sensitive. […] Routine haematological tests are also useful. A progressive decrease in the white cell count makes the diagnosis of dengue likely. Platelet counts are reduced with an increased hematocrit during 3-7 days of the illness (critical phase). […] The virus may be isolated during the viremic phase (within day 5 of illness), from serum, plasma as well as mononuclear cells in the peripheral blood.
#29 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#30 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#31 Dengue: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/215840-overview
Virus isolation, nucleic acid detection, and antigen detection are more useful to diagnose infection. […] At the end of the acute phase of illness, serology becomes the method of choice. […] The following laboratory tests should also be performed in the workup of patients with possible dengue: Complete blood cell (CBC) count, Metabolic panel, Serum protein and albumin levels, Liver panel, Coagulation panel with or without disseminated intravascular coagulation (DIC) panel. […] Guaiac testing for occult blood in the stool should be performed on all patients in whom dengue virus infection is suspected. […] Imaging studies include the following: Chest radiography, Head computed tomography (CT) scanning without contrast: To detect intracranial bleeding or cerebral edema due to severe dengue, Ultrasonography: To detect fluid in the chest and abdominal cavities, pericardial effusion, and a thickened gallbladder wall in patients with severe dengue.
#32 Dengue: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/215840-overview
Virus isolation, nucleic acid detection, and antigen detection are more useful to diagnose infection. […] At the end of the acute phase of illness, serology becomes the method of choice. […] The following laboratory tests should also be performed in the workup of patients with possible dengue: Complete blood cell (CBC) count, Metabolic panel, Serum protein and albumin levels, Liver panel, Coagulation panel with or without disseminated intravascular coagulation (DIC) panel. […] Guaiac testing for occult blood in the stool should be performed on all patients in whom dengue virus infection is suspected. […] Imaging studies include the following: Chest radiography, Head computed tomography (CT) scanning without contrast: To detect intracranial bleeding or cerebral edema due to severe dengue, Ultrasonography: To detect fluid in the chest and abdominal cavities, pericardial effusion, and a thickened gallbladder wall in patients with severe dengue.
#33 Dengue: Practice Essentials, Background, Pathophysiology
https://emedicine.medscape.com/article/215840-overview
Virus isolation, nucleic acid detection, and antigen detection are more useful to diagnose infection. […] At the end of the acute phase of illness, serology becomes the method of choice. […] The following laboratory tests should also be performed in the workup of patients with possible dengue: Complete blood cell (CBC) count, Metabolic panel, Serum protein and albumin levels, Liver panel, Coagulation panel with or without disseminated intravascular coagulation (DIC) panel. […] Guaiac testing for occult blood in the stool should be performed on all patients in whom dengue virus infection is suspected. […] Imaging studies include the following: Chest radiography, Head computed tomography (CT) scanning without contrast: To detect intracranial bleeding or cerebral edema due to severe dengue, Ultrasonography: To detect fluid in the chest and abdominal cavities, pericardial effusion, and a thickened gallbladder wall in patients with severe dengue.
#34 Evaluation of diagnostic tests: dengue | Nature Reviews Microbiology
https://www.nature.com/articles/nrmicro2459
Serological tests are more commonly used to diagnose dengue infections because of their ease of use compared to techniques such as cell culture or RNA detection. […] Several rapid diagnostic tests are commercially available and many in-house assays have been developed but the performance characteristics of many of these tests have not been adequately evaluated. […] The purpose of this guide is to establish best practice guidelines for how to design and conduct evaluations of dengue diagnostic tests for the management of acute infections, surveillance and monitoring of interventions. […] The tests that are currently used in the laboratory diagnosis of dengue infections, and their advantages and limitations, are shown in Table 1. […] Dengue virus can be isolated by the inoculation of diagnostic samples into mosquitoes, cell culture (using mosquito cell lines, such as C6/36 and AP61 or mammalian cell lines, such as Vero and LLC-MK2 cells) or intra-cerebral inoculation of suckling mice.
#35 Evaluation of diagnostic tests: dengue | Nature Reviews Microbiology
https://www.nature.com/articles/nrmicro2459
Rapid IgM-based dengue diagnostic tests have been developed as a quick and easy method for use at point of care or bedside, and exist in different formats including particle agglutination and lateral flow immunochromatographic strips, with or without plastic cassettes. […] Dengue-specific IgG-based assays can be used for the detection of past dengue infections and current infections if paired sera are collected within the correct time frame to allow the demonstration of seroconversion between acute and convalescent serum samples. […] The dramatic increase in the global burden of dengue has spurred increased public and private sector interest in developing improved diagnostics for dengue infections. […] Laboratory-based evaluations using archived serum panels can be used to determine the ability of a new diagnostic test to detect dengue infection compared to an existing method and to determine the specificity of this test with respect to other infectious agents that often co-circulate with dengue.
#36 How should we generalise the diagnosis of dengue as it spreads to more and more regions of the world? | Enfermedades Infecciosas y MicrobiologÃa ClÃnica (English Edition)
https://www.elsevier.es/en-revista-enfermedades-infecciosas-microbiologia-clinica-english-428-articulo-how-should-we-generalise-diagnosis-S2529993X2300271X
How should we generalise the diagnosis of dengue as it spreads to more and more regions of the world? […] The gold standard for direct DENV diagnosis is nucleic acid amplification tests (NAATs). […] An alternative strategy is detection of NS1 antigen (NS1Ag). […] A number of studies have evaluated different RDT for dengue. […] Rapid tests combining antigen and antibody detection may achieve sensitivity and specificity values close to 90%, making them a good option for extended surveillance. […] A recent study by Camprub-Ferrer et al. analysed the availability of RDT in the emergency department (ED) of a tertiary hospital and its impact on the management of patients requiring hospitalisation and antibiotics in a Spanish hospital. […] Similar proposals to Camprub-Ferrer et al. have been implemented with success in ED but also in less complex hospitals or Primary Care (PC) during COVID pandemic, although the clinical and epidemiological scenario are very different.
#37
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management/enhancing-dengue-diagnosis-and-case-management
Laboratory confirmation of dengue virus infection is important. Although in practice diagnosis is often made by clinical signs and symptoms only, dengue in its febrile phase cannot be clinically differentiated from other vector-borne viral and parasitic diseases, such as malaria, chikungunya and Zika fever. […] Diagnosis may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these entities. Laboratory tests using NS1 (non-structural protein 1) antigen can provide early diagnosis in febrile patients. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 4-5 days. During the acute stage of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. Serological assays to detect specific immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies to dengue virus are widely available and can provide an alternative to virus isolation or polymerase chain reaction to support the diagnosis of dengue fever.
#38
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management/enhancing-dengue-diagnosis-and-case-management
Laboratory confirmation of dengue virus infection is important. Although in practice diagnosis is often made by clinical signs and symptoms only, dengue in its febrile phase cannot be clinically differentiated from other vector-borne viral and parasitic diseases, such as malaria, chikungunya and Zika fever. […] Diagnosis may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these entities. Laboratory tests using NS1 (non-structural protein 1) antigen can provide early diagnosis in febrile patients. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 4-5 days. During the acute stage of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. Serological assays to detect specific immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies to dengue virus are widely available and can provide an alternative to virus isolation or polymerase chain reaction to support the diagnosis of dengue fever.
#39
https://www.who.int/activities/enhancing-dengue-diagnosis-and-case-management/enhancing-dengue-diagnosis-and-case-management
Mortality from dengue can be reduced to almost zero by implementing timely, appropriate clinical management that involves early clinical and laboratory diagnosis, oral and intravenous rehydration, staff training and reorganization of health services. A successful clinical outcome requires effective and early management of cases provided by clinical evaluation of hydration and recognition of comorbid conditions, accurate differential diagnosis, supported by rapid laboratory assessment/confirmation and early response to severe disease. […] The key is early recognition and understanding of the clinical problems during the different phases, especially for the treatment of dehydration and plasma leakage with oral or intravenous rehydration. For mortality from dengue, investigations (including autopsies) and clinical audits are necessary to establish the primary cause of death, the results of which should be fed back to the health care system to achieve delivery of high-quality care.
#40 SciELO Brazil – Laboratory diagnosis for dengue Laboratory diagnosis for dengue
https://www.scielo.br/j/rimtsp/a/7tYL4yQbkqSBYm4wzmmHsKd/
Effective epidemiological surveillance for dengue fever must include the ability of routine laboratory confirmation and monitoring of circulating serotypes. Laboratory surveillance is essential so that differential diagnosis could be performed between dengue fever and other acute febrile diseases, due to clinical similarities exhibited. […] In general, the dengue’s laboratory diagnosis aims: 1) laboratory, serologic and/or virologic infection’s confirmation; 2) identification of circulating serotypes; 3) laboratory confirmation of severe and fatal cases; 4) support for epidemiological investigations to determine the levels of disease transmission and 5) performance of molecular studies in order to identify existing genotypes in the region. […] The positive results for one of the following methods will confirm the case by laboratory criterion: 1) isolation and identification of dengue virus (DENV) in blood sample (serum, plasma), organ fragments collected post mortem (liver, spleen, kidney, heart, lung, nervous system); 2) detection of viral nucleic acid (RNA) using the reverse transcription-polymerase chain reaction (RT-PCR) technique; 3) detection of non-structural 1 (NS1) protein (antigen) in serum and/or plasma sample; 4) detection of IgM antibodies specific for dengue in a single serum sample; 5) increase of four times or more in the IgG antibodies titers; hemagglutination inhibiting antibodies, and/or neutralizing antibodies in paired serum samples, collected during the acute phase of illness and convalescence, for one or more DENV antigens; 6) demonstration of viral antigen in necropsied tissues by immunohistochemistry.
#41 SciELO Brazil – Laboratory diagnosis for dengue Laboratory diagnosis for dengue
https://www.scielo.br/j/rimtsp/a/7tYL4yQbkqSBYm4wzmmHsKd/
Effective epidemiological surveillance for dengue fever must include the ability of routine laboratory confirmation and monitoring of circulating serotypes. Laboratory surveillance is essential so that differential diagnosis could be performed between dengue fever and other acute febrile diseases, due to clinical similarities exhibited. […] In general, the dengue’s laboratory diagnosis aims: 1) laboratory, serologic and/or virologic infection’s confirmation; 2) identification of circulating serotypes; 3) laboratory confirmation of severe and fatal cases; 4) support for epidemiological investigations to determine the levels of disease transmission and 5) performance of molecular studies in order to identify existing genotypes in the region. […] The positive results for one of the following methods will confirm the case by laboratory criterion: 1) isolation and identification of dengue virus (DENV) in blood sample (serum, plasma), organ fragments collected post mortem (liver, spleen, kidney, heart, lung, nervous system); 2) detection of viral nucleic acid (RNA) using the reverse transcription-polymerase chain reaction (RT-PCR) technique; 3) detection of non-structural 1 (NS1) protein (antigen) in serum and/or plasma sample; 4) detection of IgM antibodies specific for dengue in a single serum sample; 5) increase of four times or more in the IgG antibodies titers; hemagglutination inhibiting antibodies, and/or neutralizing antibodies in paired serum samples, collected during the acute phase of illness and convalescence, for one or more DENV antigens; 6) demonstration of viral antigen in necropsied tissues by immunohistochemistry.
#42 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#43 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#44 Clinical Testing Guidance for Dengue | Dengue | CDC
https://www.cdc.gov/dengue/hcp/diagnosis-testing/index.html
A negative result from a RT-PCR or NS1 ELISA test does not rule out infection. […] A positive result by RT-PCR or NS1 ELISA meets the confirmatory laboratory criteria for diagnosis in the National Notifiable Diseases Surveillance System (NNDSS) dengue case definition. […] IgM ELISA is recommended as the primary test after day 7 of symptom onset. […] Patients with a positive NAAT (E.g., RT-PCR) or NS1 ELISA test have a confirmed acute dengue virus infection. […] Patients who have IgM antibodies against dengue virus in a single sample are classified as having a presumptive, recent dengue virus infection. […] All patients with clinically suspected dengue should receive appropriate management without waiting for diagnostic test results. […] Clinical samples can be referred to most state health departments or to commercial laboratories that offer dengue diagnostic testing. […] Cross reactivity is a limitation of dengue serological tests and is seen when antibodies against other flaviviruses react on the dengue IgM test. […] Current dengue molecular tests (E.g., RT-PCR) and NS1 ELISA tests do not have cross-reactivity with other flaviviruses of concern.
#45 LABORATORY DIAGNOSIS AND DIAGNOSTIC TESTS – Dengue – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK143156/
Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control: New Edition. Geneva: World Health Organization; 2009. […] Efficient and accurate diagnosis of dengue is of primary importance for clinical care (i.e. early detection of severe cases, case confirmation and differential diagnosis with other infectious diseases), surveillance activities, outbreak control, pathogenesis, academic research, vaccine development, and clinical trials. […] Laboratory diagnosis methods for confirming dengue virus infection may involve detection of the virus, viral nucleic acid, antigens or antibodies, or a combination of these techniques. After the onset of illness, the virus can be detected in serum, plasma, circulating blood cells and other tissues for 45 days. During the early stages of the disease, virus isolation, nucleic acid or antigen detection can be used to diagnose the infection. At the end of the acute phase of infection, serology is the method of choice for diagnosis. […] A range of laboratory diagnostic methods has been developed to support patient management and disease control. The choice of diagnostic method depends on the purpose for which the testing is done (e.g. clinical diagnosis, epidemiological survey, vaccine development), the type of laboratory facilities and technical expertise available, costs, and the time of sample collection. […] In general, tests with high sensitivity and specificity require more complex technologies and technical expertise, while rapid tests may compromise sensitivity and specificity for the ease of performance and speed. […] Dengue virus infection produces a broad spectrum of symptoms, many of which are non-specific. Thus, a diagnosis based only on clinical symptoms is unreliable. Early laboratory confirmation of clinical diagnosis may be valuable because some patients progress over a short period from mild to severe disease and sometimes to death. Early intervention may be life-saving. […] Before day 5 of illness, during the febrile period, dengue infections may be diagnosed by virus isolation in cell culture, by detection of viral RNA by nucleic acid amplification tests (NAAT), or by detection of viral antigens by ELISA or rapid tests. […] After day 5, dengue viruses and antigens disappear from the blood coincident with the appearance of specific antibodies. […] Dengue serologic tests are more available in dengue-endemic countries than are virological tests. […] For serology, the time of specimen collection is more flexible than that for virus isolation or RNA detection because an antibody response can be measured by comparing a sample collected during the acute stage of illness with samples collected weeks or months later. […] A four-fold or greater increase in antibody levels measured by IgG ELISA or by haemagglutination inhibition (HI) test in paired sera indicates an acute or recent flavivirus infection. […] Both the identification of virus/viral RNA/viral antigen and the detection of an antibody response are preferable for dengue diagnosis to either approach alone. […] Unfortunately, an ideal diagnostic test that permits early and rapid diagnosis, is affordable for different health systems, is easy to perform, and has a robust performance, is not yet available. […] During outbreaks some patients may be seen presenting with fever with or without rash during the acute illness stage; some others may present with signs of plasma leakage or shock, and others with signs of haemorrhages, while still others may be observed during the convalescent phase. […] One of the priorities in a suspected outbreak is to identify the causative agent so that appropriate public health measures can be taken and physicians can be encouraged to initiate appropriate acute illness management. […] The diagnostic tools used should be sensitive, specific and affordable for the country. […] The plaque reduction and neutralization test (PRNT) and the microneutralization assays are commonly used to measure protection correlates. […] The microneutralization assay is based on the same principle as PRNT. […] The haemagglutination-inhibition (HI) test is based on the ability of dengue antigens to agglutinate red blood cells (RBC) of ganders or trypsinized human O RBC. Anti-dengue antibodies in sera can inhibit this agglutination and the potency of this inhibition is measured in an HI test. […] Platelets and haematocrit values are commonly measured during the acute stages of dengue infection. […] A drop of the platelet count below 100 000 per L may be observed in dengue fever but it is a constant feature of dengue haemorrhagic fever. […] Haemoconcentration, as estimated by an increase in haematocrit of 20% or more compared with convalescent values, is suggestive of hypovolaemia due to vascular permeability and plasma leakage.
#46 Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques
https://www.mdpi.com/1999-4915/7/10/2877
Detection of DENV NS1 is a highly conserved glycoprotein, expressed as both membrane-associated and secreted forms. Secreted NS1 has been detected ranging from 2â0.04 ÂµgÂ·mLâ1 in the serum of dengue-infected patients during the early stages of the disease. A high NS1 level has been demonstrated to circulate as early as one day after onset of symptoms up to early convalescences, thus provides an alternative to virus culture or PCR for early dengue diagnosis when IgM or IgG antibodies are not present yet in dengue infected patients. […] Detection of IgM and NS1 based on RDTs and ELISA methods are the most widely used dengue assays in many countries. Although ELISA based assay have been shown to be more sensitive than RDTs, the former test lacks portability and thus, preventing its use in private clinics and field work. Because of this, many researchers have delved into biosensors as alternative new technology for the detection of DENV and dengue antibodies since this technique has several advantages such as higher sensitivity, cost-effective, simple fabrication, possible miniaturization, rapid outcome with quantitative analysis and possible on-site monitoring.