Evaluation Study of Dengue RDTs

RT-PCR and virus isolation are considered gold standard for diagnosis of Dengue from blood during first few days of infection. Serological methods such as enzyme-linked immunosorbent assays (ELISA), confirms the presence of a recent or past infection with detection of NS1 antigen and anti-dengue antibodies. However, these methods are time-consuming and need significant laboratory infrastructure, including instrumentation, trained personnel and refrigeration for reagents. Hence, in areas where DENV is endemic, have limited resources and inadequate laboratory capacity to perform these tests, rapid diagnostic tests (RDTs) can be used for quick and simple screening. Recently various RDTs which detect Antigen (NS1) and Antibodies (IgM and IgG) in single format are widely available and in use, but the performance data are not available or not consistent from one study to another. Therefore, this study aims to evaluate the sensitivity and specificity of different RDTs that detect antigens and antibodies to Dengue viruses in one cassette during acute febrile stage thereby helping healthcare providers to decide on the best test.

Dengue is an emerging infectious disease and is endemic to more than 100 tropical nations. It is a serious public health issue, with an estimated global incidence of \> 100 million in 2016, a rise of almost 60% in age-standardized rates since 2006. While rising dengue infection rates affect all major regions of the world, the Asia-Pacific region is disproportionately affected by severe dengue, with rates 18 times higher in Southeast Asia than in the Americas. Climate change and globalization has facilitated the geographic spread of both the mosquito vector and the pathogen to previously unaffected areas, thereby increasing the number of people affected by dengue. Unfortunately, no specific antiviral medication and vaccine exists for Dengue. Hence, an accurate and early diagnosis is essential for proper and timely management and control of the disease in endemic regions. Dengue causes wide spectrum of disease. Primary dengue can range from sub clinical disease to flu-like symptoms. Although less common secondary dengue is associated with increased mortality and morbidity. Accurate, efficient, and rapid diagnosis of dengue in the acute stage is essential as a delay in diagnosis increases the risk of severe dengue and can lead to poor disease outcome. The most commonly used tests to diagnose acute dengue infection are commercial ELISA. Many Dengue RDTs came in rise and flooded the market in the past two decades due to the growing demand for point-of-care diagnostics. RDT is the easiest and most cost-effective method for diagnosis of this virus infection. It is user-friendly, requires no equipment and provide results faster than PCR and ELISA. Different format of Dengue RDTs are available in the market which can detect NS1, IgM and IgG. Detection of NS1, IgM and IgG in single RDT, not only detects primary dengue but also detects past dengue infection and can be helpful in disease prognosis. Many studies have been conducted previously focusing on individual markers of dengue RDTs and not the combined assessment of the test. This has significantly impeded healthcare providers to decide on deciding which overall tests is best to diagnose acute dengue and detects past dengue in a single test format. Hence, this study will aim to perform a head-to-head comparison of Dengue RDTs which detects antigen and antibodies in single test format currently in the market to diagnose acute dengue to help stakeholder decision making more broadly.

Eligibility Criteria:
Inclusion Criteria:

* Have been obtained from patients presented with fever of \< 1 week who have given consent for sample storage for further research purpose.
* Have minimum sample volume of 1 ml.
* Are non-haemolytic
* Have a limited number of freeze-thaw cycles (\<3)
* Have been stored at or below -200C

Exclusion Criteria:

* Only samples that meet the inclusion criteria listed above will be selected for the study. Therefore, samples in the study site sample archives which do not meet these criteria will be excluded from the study.