HEPATITIS-C VIRUS-ANTIBODIES AND VIRUS-REPLICATION IN ASYMPTOMATIC BLOOD-DONORS

We assessed hepatitis C virus (HCV) infection in 99 asymptomatic blood donors positive using a first-generation HCV antibody assay. When tes ted with second-generation assays, 86 (87%) donors were reactive (grou p 1), 2 (2%) were indeterminate (group 2), and 11 (11%) were non-react ive (group 3). Viraemia was revealed by polymerase chain reaction in a ll group 1 cases. The 2 group 2 cases and 6 (55%) group 3 cases were a lso viraemic. Viraemia was confirmed by a branched DNA assay in the 2 group 2 cases and 4 (36%) group 3 cases. Serum HCV RNA levels were fur ther studied using a competitive reverse transcription-polymerase chai n reaction assay. All cases in groups 2 and 3 were low viraemic (range 10(4)-10(5.5) copies/ml) compared with the 9 group 1 cases examined ( range 10(7)-10(9) copies/ml). No correlation was evident between virae mic levels and antibody cut-off index in the first-generation assay. T hese findings indicate the possibility that low levels of viraemia can occur in individuals non-reactive in second-generation HCV antibody a ssays.