HCV Ab RIBA: Sensitivity and Specificity
RIBA (recombinant immunoblot assay), vs HCV PCR
RIBA is not intended to be used as a screening test but rather as a confirmatory test. In addition, note that there are 3 outcomes of RIBA: positive (>= 2 antigens reactivity), intermediate (1 antigen reactive), or negative. Intermediate RIBA does carry a higher PPV than negative but lower than a positive test.
94% sensitive, 94% specific