Inter-method variability of hepatitis B surface antigen quantification in a cohort of Egyptian patients with chronic hepatitis B virus

BACKGROUND AND STUDY AIMS Hepatitis B (HB) surface antigen (HBsAg) levels can predict clinical and treatment outcomes in chronic HB virus (HBV) infection. We aimed to compare the performance of two different assays [Elecsys® (Roche) and Architect™ (Abbott)] for HBsAg quantification and evaluate HBsAg levels in the various immune phases in a cohort of Egyptian patients with chronic HBV. PATIENTS AND METHODS Quantitative HBsAg by Elecsys® and Architect™ assays, measurement of routine biochemical and serological markers, and transient elastography were performed in 92 patients with chronic HBV. Results of the two assays and other tests were compared. RESULTS Ninety-two treatment-naive patients with chronic HBV, (70% males; mean age, 36.1 ± 10.5 years) were recruited from Cairo Fatemic Hospital. Patients were categorized as HBeAg positive (n = 22) and HBeAg negative (n = 70). The Architect™ and Elecsys® assays were significantly correlated (intraclass correlation coefficient: 0.913; 95% CI: 0.870-0.943; p < 0.001). However, Deming regression, Passing and Bablok, and Bland-Altman statistical analyses showed discordance among the assays. HBsAg levels by both assays were significantly higher in the HBeAg positive than patients with HBeAg-negative (p = 0.033 and 0.013, respectively). HBsAg levels in the Architect™ and Elecsys® assays were significantly higher in HBeAg-negative chronic hepatitis than in HBeAg-negative chronic infection (p = 0.002 and 0.004, respectively) CONCLUSION: Both assays for qHBsAg were found to be simple and reproducible tests that could classify patients and provide additional evidence on the natural history of HBV.