A study on evaluation and correlation of serological methods and platelet count for diagnosis of dengue virus infection

Background & objectives: Dengue is arthropod-borne, acute potentially fatal viral infection, endemic in many tropical and sub-tropical countries having public health threat globally in recent era. Effective and prompt diagnosis is very essential to reduce morbidity and mortality associated with severe form. Diagnosis by dengue-specific markers like Non-Structural protein 1 antigen or IgM/IgG antibody by serological method is the choice of investigation and the most widely used non-specific biomarker is platelet count. To evaluate and correlate results of two serological diagnostic methods (Dengue NS1 Antigen and Dengue IgM antibodies by Enzyme-Linked Immunosorbent Assay) and with platelet count for diagnosis of Dengue infection. Methods: Retrospective cross-sectional study for duration of 6 months from April 2022 to September 2022. Total 4063 serum samples of dengue suspected patients were tested according to duration of illness by ELISA for presence of NS1 Ag (≤5 days of illness) or IgM antibody (>5 days of illness). Results: 393/4063 were detected positive by either method (NS1/IgM) and majority of patients were diagnosed between 3-8 days of illness. 248/2250 were tested positive for dengue NS1-Ag only, while 145/1813 were seropositive by dengue IgM only. Thrombocytopenia (platelet counts <100000/mm 3 ) found in 301/393 seropositive cases which was also observed in NS1 (207/248 cases) and IgM (94/145 cases) seropositive patients. Interpretation & conclusion: Dengue specific parameters (NS1/IgM detection) in combination with platelet count helps in accurate, timely diagnosis and better monitoring in clinical management of patients.