Implications of occult hepatitis B infection for blood donor management: a five-year evaluation from Western Saudi Arabia

Occult hepatitis B infection (OBI), defined by detectable HBV DNA in the absence of hepatitis B surface antigen (HBsAg), remains a diagnostic challenge and a potential source of transfusion-transmitted infection. In intermediate-endemic settings such as Saudi Arabia, serology-based screening alone may miss low-level viremia. This study evaluated the prevalence, serologic patterns, and demographic correlates of OBI among blood donors. We performed a five-year retrospective analysis of 48,241 blood donors screened between November 2019 and November 2024 at a tertiary-care hospital in Jeddah. All donations were tested for HBsAg, anti-HBc, and HBV DNA using chemiluminescent immunoassays and nucleic acid testing (NAT). Anti-HBc positivity was defined as HBsAg-negative/anti-HBc–reactive. OBI was defined as HBsAg-negative with detectable HBV DNA, irrespective of anti-HBc status. Donor demographics were compared between OBI and non-OBI groups using chi-square or Fisher’s exact tests. Most donors (45,739; 94.8\%) were negative for all three HBV markers. NAT identified 92 donors (0.19\%) with OBI, including 91 classical cases (HBsAg-/anti-HBc+/HBV DNA+) and one seronegative OBI case (HBsAg-/anti-HBc-/HBV DNA+). OBI donors were predominantly male, reflecting the overall donor pool, but gender was not significantly associated with OBI. By contrast, age group and nationality differed significantly between OBI and non-OBI donors (p < 0.001 and p = 0.048, respectively), with OBI enriched among older and Saudi donors. OBI is infrequent but consistently detectable among blood donors in Saudi Arabia. Combined anti-HBc screening and highly sensitive HBV NAT improve identification of silent carriers and should inform national donor -screening and -management policies to optimize transfusion safety.