Original Research Article DOI: 10.18231/2394-5478 .2016.0012 Indian J Microbiol Res 2016;3(4):405-407 405 Comparative evaluation of a rapid test with ELISA for the detection of Dengue Infection Manmeet Kaur Gill 1,* , Amandeep Kaur 2 , Sahiba Kukreja 3 , Namrata Chhabra 4 1 Assistant Professor, Dept. of Microbiology, 2 Associate Professor, 3 Professor & Head, Sri Guru Ram Institute of Medical Sciences & Research, Sri Amritsar, Punjab, 4 Professor & Head, Dept. of Biochemistry, SSR Medical College, Belle Rive, Mauritius *Corresponding Author: Email: drmanmeetgill@gmail.com Abstract Background: Dengue is a global health issue. The clinical illness ranges from an asymptomatic febrile illness to dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). Objectives: The present study was undertaken to evaluate sensitivity and specificity of SD (BIOLINE) Dengue Duo (NS1 Ag & Ab combo) rapid test in comparison to capture ELISA for early diagnosis of dengue infection. Material and Methods: It was a tertiary hospital based retrospective cross sectional study. The data was collected by reviewing the records of 250 patients who attended the OPD or were admitted to the hospital with the suspicion of dengue infection, from May 2015 to March 2016. The blood samples were routinely processed in central clinical laboratory and were tested by both, SD (Bioline) Dengue Duo rapid test and ELISA. Results: Out of 250 samples 69 were found to be reactive for Dengue infection by ELISA. Out of these 69 seropositive samples rapid test was reactive in 55 samples. There were 18 samples in which only NS1 Ag was positive by both rapid test and ELISA. Overall sensitivity of rapid test in comparison with ELISA was found to be 79.71% and specificity was 100%. Conclusion: Early diagnosis and treatment of the patient suffering from the infection is important. SD (Bioline) Dengue Duo rapid test can be a useful tool in initial diagnosis of the infection as it detects NS1 Ag in addition to the antibodies. Its results are comparable to ELISA. Keywords: Dengue, NS1 Ag, Rapid test, ELISA Introduction Dengue is an arthropod borne viral illness caused by one of the 4 serotypes of the Dengue virus (DEN1- 4). It is worldwide in distribution especially in tropical and sub-tropical regions and is transmitted by mosquito Aedes aegypti (mainly) and Aedes albopiticus. [1] The clinical manifestations ranges from an asymptomatic febrile illness to more severe forms of infection i.e. dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). [2] In India first outbreak was reported in Kolkata in 1963-64 and gradually it spread to other parts of the country. [3] NVBDCP website data shows that dengue is endemic in 16 states of India and Punjab is one of them. [4] Over past two decades there has been increase in the number of Dengue cases and also a change in the trends of epidemiology is seen. Current diagnostics modalities available are detection of RNA of the virus with reverse transcriptase PCR (RT-PCR) in the serum of the patient which is a Gold standard test; viral isolation and serological tests like IgM capture ELISA (MAC ELISA). [5] However viral isolation and RT-PCR both are time consuming, labour intensive and expensive therefore cannot be used as routine diagnostic procedures. MAC ELISA is easy to perform so it is the most widely used serological test for the diagnosis of Dengue infection. But this test also has low sensitivity in the first week of the infection as it take 4-8 days for IgM levels to be detectable by MAC ELISA. [6] Nowadays a variety of rapid diagnostic tests (RDTs) and ELISA targeting NS1 antigen (Ag) are available commercially. [7-9] NS1 is a highly conserved Dengue virus specific non- structural protein and is detectable early during the acute phase (Day 0 to 9 of fever) of both primary and secondary Dengue virus infection. [10] The present study was undertaken to evaluate the sensitivity and specificity of rapid SD (bioline) Dengue Duo (NS1& Ab combo) test in comparison to ELISA (NS1, IgG, and IgM). Material and Methods Study design & Data collection: It was a retrospective cross sectional study carried out in a tertiary care hospital attached to S.G.R.D Institute of Medical Science and Research, Amritsar, North India. The data was collected by reviewing the records of 250 patients who attended the OPD or were admitted to the hospital with the suspicion of dengue infection, from May 2015 to March 2016. The blood samples of these patients were routinely processed for dengue infection in central clinical laboratory of the hospital. Serum was separated and each sample was tested with both SD Bioline Dengue Duo rapid test as well as ELISA. SD Bioline Dengue Duo test is an in vitro immuno-chromatographic rapid which provides results within 20 minutes. It is a two test device in which one side is for qualitative