Serodiagnosis of dengue using NS1 antigen, dengue IgM, dengue IgG antibody with correlation of platelet counts

Introduction: The dengue virus causes one of the most important mosquito-borne viral diseases.Annually, it affects up to 100 million people. Early laboratory diagnosis of dengue infection isimportant, as itcan allow early intervention and better prognosis. Dengue IgM antibody isdetected usually after five days of infection. NS1 antigen can be detected as early as day one.Platelet count is the only non-dengue parameter that can support the diagnosis of the dengueshock syndrome (DSS) and dengue hemorrhagic fever (DHF). This study was done to correlate the platelet count and dengue parameters detected either by rapid card test or by ELISA methods. Materials and Methods: Five hundred ninety three clinical samples suspicious of dengue were collected from April2020 to September2020. The received samples were tested by rapid methods and ELISA for dengue parameters and for platelet count by automated Becmon Coulter5partcellanalyser. Results: Out of 593 samples, 90 samples were positive by rapid tests that included NS1 antigentest, IgM and IgG dengue by immune chromatographic tests. Sixty one samples were positive bydengue IgM and dengue IgG ELISA.Samplespositivefordengue IgM antibodies orNS1antigen alone or positive for both were classified as primary dengue infection. Samples positivefor dengue IgG antibody or dengue IgG and IgM antibodies were classified as secondary dengue infections. Of the 90 cases positive by rapid card test, 62 cases were classified as primary dengueinfection and 28 cases as secondary dengue infection. Total 61 cases were positive by ELISAtests of these 35 cases were diagnosed as primary dengue and remaining 26 cases as secondary dengue infection. Conclusion: Thus the rapid tests such as NS1 antigen test, IgM and IgG dengue antibody can be used for the diagnosis in small peripheral laboratories. Thrombocytopenia was more consistent with cases positive for only IgG. Though MAC ELISA is more sensitive and specific than rapid methods, detection of NS1 antigen by immunochromatograpy test helps in early detection