The contribution of more sensitive hepatitis B surface antigen assays to detecting and monitoring hepatitis B infection.

Abstract Background Hepatitis B surface antigen (HBsAg) remains the main viral marker for screening and monitoring hepatitis B virus (HBV) infection. The quantification limit of most current HBsAg assays is around 0.05 IU/mL. The Lumipulse-G-HBsAg-Quant assay (Fujirebio) claims to obtain a tenfold improvement in sensitivity. This study aimed to assess the performance of this assay in detecting low HBsAg levels in clinical samples. Methods Three panels of stored frozen samples were selected on the basis of HBV-DNA and HBsAg values obtained previously with routine techniques. Panels 1 (n=13) and 2 (n=52) consisted of DNA-positive/HBsAg-negative samples from individuals in the window period and with occult HBV infection respectively. Panel 3 comprised 23 samples with low or discrepant HBsAg screening results. All these samples were tested retrospectively with the DiaSorin and Fujirebio HBsAg assays. Results Sixteen out of 65 samples (25 %), initially screened HBsAg negative, were reactive only with the Fujirebio assay (median value= 0.015 IU/mL; IQR= 0.012): three (23 %) samples from panel 1 and 13 (25 %) from panel 2. Thirteen of these 16 (81 %) had HBsAg values below 0.03 IU/mL with the DiaSorin assay. In panel 3, 22 (96 %) samples were quantified successfully with the Fujirebio assay (median: 0.32 IU/mL; IQR: 1.20) and 19 (83 %) with the DiaSorin assay (median: 0.31 IU/mL; IQR: 0.65). Concentrations obtained with the two assays showed good correlations (r=0.893, Spearman). Conclusions HBsAg assays with enhanced analytical sensitivity could improve HBV serological profile interpretation with possible consequences on clinical management of infected patients, and on blood transfusion safety.