Methods: We determined the percentage of true vs false-positive HCV antibody (anti-HCV) test results among participants in a nationally representative study (NHANES) with low HCV infection prevalence using a confirmatory recombinant immunoblot assay (RIBA) test and follow-up HCV RNA testing.
Results: Overall, of 22,359 NHANES participants tested, 479 (2.1%) were anti-HCV screening reactive and were tested for RIBA; of 477 tested by RIBA, 323 (67.7%) were true positives (RIBA-positive), and 105 (22%) were false positives (RIBA-negative) (see Figure). Many others (49, 10.3%) were RIBA indeterminate of which only 2 (4.9%) represented active infection. Ultimately, of 424 with more (RIBA and HCV RNA) testing, 218 (51.4%) were confirmed as active HCV infections.
Conclusion: False-positive antibody assays may occur with great frequency when screening low HCV prevalence populations, emphasizing the need for �reflex� HCV RNA testing to avoid clinician and patient confusion and distress.
S. D. Holmberg,
J. Drobeniuc, None
S. Kamili, None