CONFIRMATORY STRATEGY OF HEPATITIS-C SEROLOGY BASED ON 2 SCREENING ASSAYS IN A DIAGNOSTIC SETTING

One hundred ninety seven successive sera, positive for anti-hepatitis C virus antibody with a third generation screening enzyme immunoassay (MEIA on IMX, Abbott), were tested with alternative third generation s creening assays from two different manufacturers (Sanofi and Ortho), w ith an immunoblot assay (RIBA 3.0, Chiron), and by reverse transcripta se polymerase chain reaction (RT-PCR). Samples positive by RIBA 3.0 or by RT-PCR were considered as true positives. The positive predictive value of a combination of strong positive results in two screening ass ays was more than 98%. This combination of results has the same predic tive value for detectable viraemia as a positive RIBA 3.0 (86.5%). Usi ng a policy of two successive enzyme immunoassays in this clinical dia gnostic setting diminishes the need for supplemental assays by more th an 85%.