Six strategies for identifying hepatitis C virus (HCV)
viremia, involving testing for HCV antibody (HCVAb) followed by a
nucleic acid test (
NAT) for HCV
RNA when the antibody test is positive, are compared. Decision analysis was used to determine mean relative cost per person tested and outcomes of HCV
viremia detection. Parameters included proportions of test population with HCVAb and
viremia plus specificity, sensitivity, and cost of individual tests. For testing a population with an HCVAb seroprevalence of 3.25%, all strategies when adopting quantitative
NAT vary little in cost (range, $29.50-$30.70) and are highly
viremia specific (≥0.9997). Four of the strategies using venipuncture blood for HCVAb testing (whether laboratory conducted or employing a rapid, point-of-care assay) and for
NAT (whether done by reflex or using separately drawn blood) achieve the highest
viremia sensitivities (range, 0.9950-0.9954). Point-of-care HCVAb testing in fingerstick blood followed by
NAT in venipuncture blood yields relatively lower
viremia sensitivity (0.9301). The strategy that requires returning for
NAT is even less
viremia sensitive (<0.9000) because of follow-up loss. Strategies adopting qualitative rather than quantitative
NAT are slightly cheaper (range, $28.90-$29.99), similarly
viremia specific (≥0.9997), but less
viremia sensitive (≤0.9456).
Viremia sensitivity and specificity remain the same regardless of the proportion of HCVAb-seropositive persons in the cohort being tested.
CONCLUSIONS: Strategies involving HCVAb testing in venipuncture blood, whether laboratory conducted or using a point-of-care assay, when followed by quantitative
NAT done reflexively or in separately drawn blood, are comparably economical and suitably
viremia sensitive. Less cost-effective is point-of-care HCVAb testing in fingerstick blood followed by
NAT in venipuncture blood. Least cost-effective is the strategy requiring the tested person to return for
NAT.