High risk of occult hepatitis B virus infection in HIV-positive patients from South Africa.

This was a retrospective, unmatched case control, laboratory-based study, investigating the impact of human immunodeficiency virus (HIV) infection on the outcome of routine laboratory detection of HBsAg and prevalence of active HBV infection in 295 samples from 167 HIV-positive and 128 HIV-negative patients. The samples were tested for HBV (HBsAg, anti-HBc, anti-HBs, HBeAg and anti-HBe) and anti-HIV 1 and 2 (Axsym assays, Abbott Laboratories), as part of routine diagnosis. A nested PCR assay, with detection limit of 800 copies/ml and employing independent sets of primers to core and surface genes, was used to investigate HBV DNA.