1Veterans Affairs Paget Sound Health Care System and University of Washington, Seattle, WA.
2Veterans Affairs Medical Center, Washington, DC.
3Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA.
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 HCV antibody 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.
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.