Prescreening with a Rapid Diagnostic Test Followed by a Confirmatory Qualitative Nucleic Acid Test Can Simplify Hepatitis C Diagnosis

Asymptomatic hepatitis C virus (HCV) infection without treatment is associated with chronic liver diseases including hepatocellular carcinoma. A major obstacle to hepatitis C diagnosis leading to antiviral treatment in some developing countries is the complicated HCV testing required before treatment. To simplify an HCV test-to-treat strategy, which could lead to timely diagnosis and treatment at the point-of-care, we evaluated the performance of four anti-HCV rapid diagnostic tests (RDTs) (Abon, Blue Cross, Healgen, and SD Bioline). They yielded comparable sensitivity (80-83%), specificity (99-100%), and accuracy (90-91.5%). When we field-tested Abon in 4,769 residents of an HCV-endemic province in Thailand, 306 seropositive individuals (6.4%) were identified. In comparison, laboratory test using an automated commercial chemiluminescent microparticle immunoassay (Abbott ARCHITECT) identified slightly more seropositives (327% or 6.9%). Field implementation suggests that Abon was sensitive (88.7%), specific (99.6%), and accurate (98.9%). Furthermore, 82% (250/306) of Abon-positive samples had detectable HCV RNA as determined by nucleic acid test (Roche cobas). The same 250 samples out of 327 reactive in Abbott immunoassay also had detectable HCV RNA (mean RNA level: log 6.28 IU/mL, range: log 3.06- 7.78 IU/mL). The use of RDT followed by qualitative nucleic acid test can cost-effectively identify the majority of HCV seropositive individuals with active infection, which will obviate the need for expensive viral load quantification tests when simplifying HCV diagnosis for the test-to-treat program at the point-of-care.