Association of serological parameters and platelet counts in dengue fever: A hospital-based study.

BACKGROUND: Dengue fever (DF) is an acute febrile arboviral disease affecting the tropical and subtropical regions of the world. It is known that early and specific diagnosis of dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), followed by supportive therapy, reduces morbidity and mortality. Serum levels of secreted NS1 positively correlate with viral titers and have been a useful tool in dengue infection (DI) diagnosis. NS1 detection is reported to be sensitive as well as highly specific. Apart from the dengue-specific parameters, platelet count is the only accessory laboratory test available in the peripheral areas that can support the diagnosis of DHF or DSS. In this study, we tried to correlate the platelet counts and immunochromatography (ICT)-based dengue serology tests. METHODS: A total of 525 serum samples from clinically suspected DF were collected. The samples were tested immediately for NS1, immunoglobulin M (IgM), and IgG by ICT-based tests. Platelet counts of all the cases positive for any of the dengue parameters were noted. The statistical analysis was performed using Z-test. RESULTS: One hundred and nine specimens were tested positive for either one or more of the three markers (NS1, IgM, and IgG). Platelet count <1,00,000/ml was noticed in 65 cases (%) of 109 dengue-positive cases. Of 79 cases who were positive for NS1 antigen only, thrombocytopenia was observed in 44 cases, whereas thrombocytopenia was observed in six of six cases positive for NS1 + IgM. The association of thrombocytopenia in NS1 + IgM-positive cases was statistically significant (Z = 2.125, P = 0.0331). CONCLUSION: In the present study, association of thrombocytopenia in dengue parameter-positive cases was found to be highly significant. ICT is the only excellent tool as it is easy, rapid, and easily available in areas with poor resources. Apart from dengue-specific parameters, platelet count is the only accessory laboratory test available in the peripheral areas that can support the diagnosis of DI. [ABSTRACT FROM AUTHOR]