Missed opportunities: ALT and anti-HBc as surrogate tests for hepatitis.

ALT and anti-HBc came into use in the US as surrogate tests for non-A, non-B hepatitis by 1986-1987, generally using cutoffs at 50-60 IU/L. We studied the usefulness of anti-HBc, and of ALT at different cutoffs as surrogate tests for hepatitis C virus, recording and analyzing the ALT, anti-HBc, HBsAg, and RIBA results of 175 non-autologous blood donations in 1993 and 1994 that had positive second generation screening tests for anti-HCV. ALT levels of 1014 blood donations also were studied. Only 93 of 175 anti-HCV-positive donations were RIBA positive. Of these, anti-HBc would have excluded 23%, an ALT cutoff at 60 IU/L would have excluded 42% and an ALT cutoff at 40 IU/L would have excluded 70% (plus 5.6% of all donations). Both tests together would have been better than either alone. No tests for HBsAg were positive. ALT and anti-HBc clearly were useful surrogate tests for hepatitis C. If they had been used sooner and with lower ALT cutoffs, many people would have avoided post-transfusion hepatitis in the years before anti-HCV testing was available.