Prospective study to compare results of FIA (fluorescent immunoassay) test with gold standard ELISA test in Dengue NS1 patients admitted in a tertiary care hospital

Abstract

PurposeThe objective of this study was to compare the performance of STANDARD F Dengue NS1 Ag FIA SD Biosensor and ELISA for diagnosis of dengue in patients admitted in a tertiary care hospital. The results of the FIA test were compared with ELISA test, the gold standard in terms of sensitivity, specificity, positive predictive value, negative predictive value. MethodsTotal 19,890 patients suffering from acute febrile illness suspecting dengue were screened for dengue NS1 antigen by rapid immunochromatography test during the period of one year and six months from June 2020 to November 2021. Out of them, a total of 300 blood samples were selected by simple random sampling method for the study. The blood samples were collected and subjected to dengue NS1 ELISA and FIA test according to the kit literature. ResultsOut of total 300 samples, 67.67% (203) patients were positive for dengue NS1 antigen by FIA test. Total 200 patients (66.67%) were positive for dengue NS1 antigen by ELISA and (190) 63.33% were positive for dengue NS1 antigen by rapid ICT.It was also seen that there was an inverse relation between the Cutoff Index (COI) value of FIA and the platelet count of the dengue NS1 positive patients. ConclusionWe conclude that the results of Dengue NS1 Microwell ELISA test and Dengue NS1 FIA test are almost equivalent in relation to sensitivity, specificity, positive predictive value, and negative predictive value.FIA gives rapid test results, thus is time saving and can be routinely used. The COI value can also give a relative idea about the severity of the disease.