Discrepancies in hepatitis B surface antigen testing: A systematic review of false-positive results and underlying mechanisms with implications for laboratory hematology

Hepatitis B surface antigen (HBsAg) testing remains a cornerstone in the diagnosis and screening of hepatitis B virus (HBV) infection, particularly in hematological contexts such as blood donor screening and transfusion medicine. However, false-positive results pose significant challenges, leading to unnecessary interventions, psychological distress, and resource strain in clinical hematology laboratories. This systematic review synthesizes evidence on the discrepancies in HBsAg assays, focusing on false positives and their etiological mechanisms. A comprehensive search of PubMed, Web of Science, and Scopus databases from January 2000 to October 2025 identified 1,247 records, with 42 studies meeting the inclusion criteria after screening. Key findings reveal that false positives occur at rates of 0.1–9% across assays, predominantly due to heterophilic antibody interference (25% of cases), recent HBV vaccination (15–20%), and iatrogenic factors like granulocyte-colony stimulating factor administration (10%). Novel insights highlight hematology-specific contributors, including rheumatoid factor in autoimmune hemolytic anemias and mutant strains in immunocompromised patients. Chemiluminescent immunoassays (CLIAs) exhibit higher specificity (99.8%) than enzyme-linked immunosorbent assays ([ELISAs]; 98.5%), but discrepancies persist in low-prevalence settings. This review proposes a refined diagnostic algorithm incorporating confirmatory neutralization assays and molecular HBV DNA testing to mitigate errors. By addressing these gaps, laboratories can enhance accuracy in hematological screening, reducing false positives by up to 40%. Future research should prioritize multiplex assays integrating hematological biomarkers for real-time interference detection.