AGE, SEX AND TRANSAMINASE DEPENDENCY OF SPECIFIC AND NONSPECIFIC RESULTS FROM ENZYME IMMUNOASSAYS FOR ANTIBODIES TO HEPATITIS-C VIRUS AND FOLLOW-UP OF BLOOD-DONORS

Background: Second-generation enzyme immunoassays (EIA-2) for antibodi es to hepatitis C virus (anti-HCV) have an improved specificity and se nsitivity compared to first-generation enzyme immunoassays (EIA-1). Th erefore the question arises how many anti-HCV-positive blood donors we re missed by the EIA-1, how many were false positive, how false-positi ve donors should be dealt with and how the results of the EIA-2 correl ate with demographic data and-surrogate testing for serum alanine amin otransferase (ALT). Material and Methods: A total of 208,544 individua l North German blood donors not preselected for anti-HCV negativity we re tested for anti-HCV with EIA-2 and, if repeatedly reactive (rr), wi th a licensed supplementary test (RIBA-2). Results: Overall, 0.43% of the donors were EIA-2 rr, but only 0.12% of women and 0.09% of men wer e RIBA-2 positive. RIBA-2 positivity rates were very low in donors 18 to 27 years old (0.03% and 0.05%) and clearly rose with age in women b ut not in men. The rate of unspecifically positive EIA-2 results (enti rely negative in RIBA-2) rose with age in both sexes and did not corre late with ALT. The ALT distribution was age dependent with a completel y different pattern for men and women. Anti-HCV positivity was strongl y correlated with ALT albeit on a very low level: more than 97% of don ors with strongly elevated ALT were anti-HCV negative. Follow-up and c omparison of EIA-1, EIA-2 and RIBA-2 results for the subsequent donati ons showed that only 8% of now RIBA-2-positive donors were not detecte d by EIA-1. Apparent seroconversions in EIA-2 are usually not specific : only one out of 66 apparent seroconversions could be confirmed by RI BA-2. 0.15% of the donor population showed an inconsistent EIA-2 patte rn during follow-up. Conclusions: We therefore suggest that donors sho uld not be excluded from further donations on the basis even of multip le EIA-1 positive results or on the basis of only one EIA-2-positive d onation. The value of ALT screening for transfusion safety should be r econsidered.