Detection of antibodies against hepatitis C virus in saliva: a marker of viral replication.

Hepatitis C surveillance has been restricted owing to the lack of a sensitive antibody assay for saliva. The aim of our study was to develop and evaluate a screening assay for hepatitis C antibody in saliva specimens. Serum/saliva pairs were collected from 115 hepatitis C-positive patients. A modified hepatitis C antibody assay for saliva was developed and linked to testing carried out in the diagnostic laboratory. Correlation between the presence of antibody in serum and in saliva was poor (100% vs 85%). However, of 98 patients who were saliva antibody positive, 96 (98%) were also serum hepatitis C RNA positive and two (2%) were serum hepatitis C RNA negative. Hence, the correlation between a positive salivary antibody test and the serum hepatitis C RNA status of intravenous drug users suggests that this test could be used as a surrogate marker for hepatitis C viraemia in epidemiological studies.