USE OF POLYMERASE CHAIN-REACTION AND ANTIBODY TESTS IN THE DIAGNOSIS OF VERTICALLY TRANSMITTED HEPATITIS-C VIRUS-INFECTION

Data on patterns of polymerase chain reaction (PCR) and antibody test results in infants born to hepatitis C virus (HCV)-infected mothers we re systematically reviewed to aid development of optimum testing sched ules and diagnostic criteria for vertically exposed infants and to fac ilitate early identification of infected infants, Survival and cross-s ectional analyses were used to estimate the timing of initial PCR posi tivity and subsequent PCR negativity in infected infants, and maternal antibody loss in uninfected infants was estimated as a weighted avera ge of individual study findings, Of 74 eligible infants with strong ev idence of HCV infection, an estimated 89% (90% confidence interval, 80 -95%) were first PCR positive by 3 months of age, and less than 10% ha d subsequent PCR negativity attributable to intermittent viraemia or r esolved infection in the first 18 months of life, The negative predict ive value of PCR at 3 months of age was greater than 98% at an assumed rate of 5% vertical transmission, but as low as 88% at 25% transmissi on, The inclusion of 22 infants, each with a single PCR-positive resul t, increased the estimated frequency of resolved infections but made l ittle difference to other estimates, A minority of PCR-positive infant s had periods of antibody negativity by second-or third-generation ass ays, and among 297 uninfected infants, maternal antibody was not detec ted beyond 18 months, Thus, the majority of infected infants may be pe rsistently PCR positive from 3 months of age, and the negative predict ive value of PCR at 3 months is generally high, However, poor repeatab ility of PCR, inadequate infant follow-up, and inclusion of postnatall y infected infants limits interpretation of the pooled data, Further s tudies using standardised PCR methodologies are needed.