EVALUATION OF BLOOD-DONORS WITH EQUIVOCAL HEPATITIS-C SEROLOGICAL RESULTS

Objective: To characterise blood donors with equivocal hepatitis C ser ological results and to develop an algorithm for their diagnosis and f ollow-up. Design: Prospective case survey. Subjects and setting: 100 c onsecutive blood donors referred to the St Vincent's Hospital Liver Cl inic, Victoria, with equivocal hepatitis C serological results (positi ve result for second generation Abbott Enzyme Immunoassay 2.0, but at least one negative result on supplemental testing by first generation Abbott neutralisation assay and Abbott Supplemental Assay for antibody to specific viral antigens). Outcome measures: Percutaneous risk fact ors for hepatitis C exposure, peak serum alanine aminotransferase (ALT ) levels, results of alternative immunoassay (Monolisa) and polymerase chain reaction (PCR) to detect hepatitis C viraemia. Results: Thirty subjects had positive results for alternative immunoassay. A risk fact or was identified for 32 subjects and was significantly associated (P< 0.01) with positive results for alternative immunoassay (23/32) and PC R (11/32), abnormal ALT levels (7/32), and strong reactivity on initia l immunoassay (23/32). Presence of antibodies to both structural and n on-structural antigens was associated with risk factors positive alter native immunoassay results. Conclusions: A definitive diagnosis was po ssible in 87% of subjects. A diagnosis of hepatitis C infection was ba sed on positive alternative immunoassay results together with positive PCR results or presence of a risk factor. Hepatitis C was excluded fo r 60% of patients. The diagnosis for the remaining 13% remained indete rminate, indicating the need for a definitive diagnostic test for hepa titis C.