Comparative study of the prevalence of HIV using the third- and fourth-generation HIV ELISA in blood donors in South India

INTRODUCTION: Different generations of ELISA have evolved over the years. With the introduction of the fourth-generation ELISA, there is a claim of higher sensitivity over the third-generation HIV ELISA kits. However, few literatures suggest false positive issues. The present study aimed to assess the seroprevalence of HIV and to see the level of agreement between the third- and fourth-generation ELISA for HIV detection. METHODOLOGY: Prospective cross-sectional study conducted in a tertiary care hospital from November 2021 to May 2023. All positive samples by either the third- or fourth-generation ELISA were included in the study. If any sample was positive in one generation, and the same whole batch was repeated in another generation ELISA. All positive samples were subjected to molecular testing by polymerase chain reaction. Cohen's kappa coefficient was used to see the level of agreement between the thrid and fourth-generation HIV ELISA. RESULTS: Seventeen samples were positive by the third-generation ELISA versus 50 samples were positive by the fourth-generation ELISA. The prevalence of HIV was found to be 0.9% by the fourth-generation ELISA and 0.3% by the third-generation ELISA. There was a fair level of agreement between the third- and fourth-generation HIV ELISA. Both generations have a sensitivity of 100%, whereas specificity with the third generation was 91% and the fourth was 24%. CONCLUSION: Both the fourth- and third-generation ELISA are highly sensitive; however, the specificity of the fourth-generation kit is less, leading to more false positive results.