Jm. Pawlotsky et al., WHAT STRATEGY SHOULD BE USED FOR DIAGNOSIS OF HEPATITIS-C VIRUS-INFECTION IN CLINICAL LABORATORIES, Hepatology, 27(6), 1998, pp. 1700-1702
The aim of this study was to determine a cost-effective strategy for t
he diagnosis of hepatitis C virus (HCV) infection in clinical laborato
ries. Anti-HCV antibodies were sought in 3,014 consecutive unselected
samples with two different enzyme-linked immunosorbent assays (ELISA).
An immunoblot-based confirmatory assay (RIBA3.0) was performed in the
samples with at least one ELISA positive or weakly positive. HCV RNA
was evaluated using HCV polymerase chain reaction (PCR) in the samples
with a weakly positive ELISA, discrepant results of the two ELISAs, o
r an indeterminate RIBA3.0 pattern. The two ELISAs gave concordant res
ults in 2,957 (98.1%) of the 3,014 samples (negative in 87.9%, positiv
e in 11.8%, and weakly positive in 0.3%), and discrepant results in 57
(1.9%), RIBA3.0 was positive in 338 of the 350 ELISA-positive samples
(96.6%) and indeterminate in 12. Six of them were PCR-positive, Among
the 8 weakly positive samples, 1 was RIBA3.0-positive, 6 were RIBA3.0
-indeterminate, and 1 was RIBA3.0-negative; all were PCR-negative. Amo
ng the 57 samples with discrepant ELISA results, 4 were RIBA3.0-positi
ve (none were PCR-positive), 22 were RIBA3.0-indeterminate (1 was PCR-
positive), and 31 were RIBA3.0-negative (6 were PCR-positive). In thes
e cases, the clinical context and PCR detection of HCV RNA allowed for
definitive classification. In conclusion, one single ELISA determinat
ion is necessary for diagnosis of HCV infection in clinical laboratori
es, and confirmation of positive or weakly positive ELISAs with immuno
blot-based confirmatory assays is no longer needed. HCV-RNA detection
by PCR helps to resolve weakly positive or negative ELISA results when
the clinical context is compatible with hepatitis C.