Comparison of rapid dengue NS1, qualitative ELISA, and quantitative ELISA result

Background: Non-structural glycoprotein-1 (NS1) is a useful biomarker for early diagnosis of dengue fever. NS-1 antigen ELISA can be used for the early diagnosis of dengue fever in the acute stage. Quantitative methods are better for epidemic settings due to high false negative rates in qualitative ELISA. Methods: The study was initiated after approval from the institutional ethics council (IEC/DISS/17118). Study examined 280 patients with dengue symptoms who presented to the hospital's OPDs and IPDs. Patients were tested using qualitative ELISA, and those with Leptospira antibody, malaria, or Chikungunya IgM antibody were excluded. Age, gender, symptoms, comorbidities, total leucocyte count, platelet count, and risk category were all patient-related parameters. Patient-related parameters were recorded, and data was collected using Microsoft excel and analysed statistically. Results: Most patients aged 2-40 with male predominance had fever, chills, and body aches, 243 (86.8%) tested positive for ELISA NS1. Quantitative ELISA test showed a statistically significant correlation with rapid antigen NS1 result (p=0.015). Its AUC was 0.883 (p=0.0001), and its cut-off was (>109.1) with 96.9% sensitivity and 13.64% specificity. The AUC of quantitative ELISA NS1 against qualitative ELISA NS1 was 0.853 which was statistically significant (p<0.0001). At the cut-off >74.34, the test's sensitivity was 92.59% and specificity was 75.68%. Conclusions: Qualitative ELISA NS1 test is better than rapid antigen test for screening due to its higher specificity and similar sensitivity.