Identification of occult hepatitis B infection despite high anti-HBs in a hemodialysis patient during pretransplant evaluation.

Occult hepatitis B virus infection is characterized by detectable hepatitis B virus DNA in individuals who test negative for hepatitis B surface antigen (HBsAg). In patients awaiting kidney transplantation, unrecognized occult hepatitis B virus infection may increase the risk of viral reactivation following immunosuppressive therapy. However, hepatitis B screening in many clinical settings still relies primarily on HBsAg and anti- HBs testing, which may fail to identify occult infection. We report the case of a 39-year- old woman with end-stage renal disease receiving maintenance hemodialysis who was evaluated for kidney transplantation. Routine serological screening showed negative HBsAg and a high anti-HBs titer (292.3 IU/L), suggesting resolved hepatitis B virus infection. However, further evaluation revealed positive total anti-HBc and detectable serum hepatitis B virus DNA with a viral load of 9.54 × 103 lU/mL. Hepatitis B e antigen (HBeAg) was negative and liver enzyme levels were within normal ranges. These findings were consistent with occult hepatitis B virus infection. This case highlights a potential diagnostic pitfall when hepatitis B screening relies solely on HBsAg and anti-HBs testing. A more comprehensive evaluation, including anti-HBc and hepatitis B virus DNA testing, should be considered in high-risk populations to avoid missed occult infection and reduce the risk of hepatitis B virus reactivation after transplantation.