PCR-based efficacy assessment of hepatitis B core antibody and hepatitis B surface antigen screening tests in the blood donor population

Abstract

Objectives: To assess the screening efficacy of HBsAg and HBcAb serological assays in comparison with Polymerase Chain Reaction (PCR), as the gold standard.
Methodology: This was a cross-sectional prospective study was conducted from November 2019 to February 2020, at the Department of Pathology and Transfusion Medicine, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan. A total of 7,550 donations were screened for HBsAg through Chemiluminescence Microparticle Immunoassay. Out of 7,550, 186 HBsAg reactive, and 208 HBsAg non-reactive samples were selected randomly for the study. The screening tests for HBsAg and HBcAb were run in parallel with PCR as the gold standard. In the statistical analyses, the specificity, sensitivity, and positive and negative predictive values were calculated using the PCR results as the gold standard. Kappa agreement was also calculated. 
Results: A total of 394 blood samples were tested with reactivity rate of HBsAg (n= 186) 47.2% (186/394), HBcAb (n= 210) 53.2% (210/394) and PCR (n= 188) 47.7% (188/394). Kappa agreement for HBsAg and HBcAb were calculated as 0.961 and 0.886 respectively. The results showed 5.5% false positive results by HBcAb test.
Conclusion: HBcAb screening showed false-positive results. HBsAg screening found to be the best possible choice that can give credible results, considering the high cost of the molecular assays.