COMPARATIVE EVALUATION OF QUANTITATIVE PCR AND HBSAG ELISA FOR DETECTION OF HEPATITIS B VIRUS INFECTION: A CROSS-SECTIONAL STUDY FROM PAKISTAN

Abstract

Background: Hepatitis B virus (HBV) infection affects over 400 million people globally and remains a major cause of cirrhosis and hepatocellular carcinoma (HCC). Accurate and timely diagnosis is critical for effective management, yet diagnostic capacity varies widely across resource-limited settings.

Objective: To compare the diagnostic performance of quantitative PCR (qPCR) and HBsAg enzyme-linked immunosorbent assay (ELISA) for the detection and monitoring of HBV infection in a hospital-based cohort in Pakistan. Methods: In this cross-sectional study, 60 HBV-confirmed patients (35 male, 25 female; mean age 43.85 ± 14.67 years) were enrolled from Govt Teaching Hospital Shahdara, Lahore. Each participant underwent parallel testing by qPCR (HBV DNA viral load) and HBsAg ELISA. Statistical analyses included the Shapiro-Wilk normality test, Spearman rank correlation, and Kruskal-Wallis test (SPSS v25).

Results: A highly significant positive correlation was observed between ELISA optical density and HBV viral load (Spearman rₛ = 0.862, p < 0.0001). Median viral load was significantly higher in ELISA-positive patients (33,715 IU/mL) compared to borderline (2,595 IU/mL) and negative (3,046 IU/mL) groups (Kruskal-Wallis H = 11.269, p = 0.004). Importantly, two patients (3.3%) were ELISA-negative yet had detectable HBV DNA by qPCR (809 and 5,283 IU/mL), indicating occult HBV infection (OBI). No significant differences in viral load were observed by age or sex.

Conclusion: ELISA demonstrates strong concordance with quantitative HBV viral load and remains a valuable cost-effective screening tool. However, qPCR is indispensable for detecting OBI and low-viremia cases. A complementary diagnostic approach ELISA for first-line screening and qPCR for confirmation and monitoring is recommended for comprehensive HBV management in Pakistan and similar endemic settings