Comparative Evaluation of a Rapid Screening Test and Enzyme-linked Immunosorbent Assay for Hepatitis B Surface Antigen Detection.

Hepatitis B virus (HBV) belongs to the Hepadnaviridae family and is a DNA virus, composed of a nucleocapsid core and an outer envelope. It spreads through blood, needle-stick injuries, sexual contact, and vertical transmission from mother to child. The earliest marker of infection is hepatitis B surface antigen (HBsAg), detectable weeks before symptoms. According to the WHO, 254 million people lived with chronic HBV in 2022, with 1.2 million new infections annually. HBV causes serious liver complications, including chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Diagnosis relies on serological and molecular tests, such as the immunochromatographic test (ICT), enzyme-linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), and nucleic acid amplification testing (NAT). While ELISA, EIA, and NAT are highly sensitive but costly, ICT is a rapid, affordable, and valuable for screening; however, they carry a risk of false results compared to ELISA. The aim of this study was to evaluate and compare the diagnostic performance of rapid immunochromatographic test (ICT) with ELISA in HBsAg detection. A cross-sectional study was conducted from August 2024 to April 2025 in the Department of Microbiology, Sri Ramachandra Institute of Higher Education and Research, Chennai. A total of 220 serum samples were included in the study. Each sample was tested for HBsAg using both rapid ICT and ELISA. Results were analyzed for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's Kappa(κ) coefficient. Of 220 samples, 42 (19.1%) were positive and 178 (80.9%) were negative by both methods. No false positives or false negatives were observed. ICT showed 100% sensitivity, specificity, PPV, and NPV, with Cohen's κ = 1.0 (P < 0.001), indicating perfect agreement with ELISA. ICT showed excellent diagnostic accuracy comparable to ELISA, supporting its use as a reliable and cost-effective screening tool in clinical and resource-limited settings. However, borderline results require confirmatory testing with ELISA or molecular methods. This study aligns with the United Nations Sustainable Development Goal 3: Good Health and Well-Being by supporting the development of affordable and accessible diagnostics for the elimination of viral hepatitis.