Performance characteristics of a combined hepatitis C virus core antigen and anti–hepatitis C virus antibody test in different patient groups

We evaluated the performance of a hepatitis C virus (HCV) antigen/antibody combination test [Murex HCV Antigen/Antibody Combination Test (Murex Ag/Ab test)] by comparing it with the current third-generation HCV antibody enzyme immunoassay (anti-HCV). A total of 403 serum samples were consecutively collected from four patient groups: healthy controls (n = 100); HCV-infected patients (HCV group, n = 102); Human immunodeficiency virus (HIV)/HCV-infected patients (HIV/HCV group, n = 100); and patients with uremia (uremia group, n = 101). Performances were evaluated for the Murex Ag/Ab, anti-HCV, and HCV RNA in the HIV/HCV and uremia patient groups. In the HCV group, all 102 samples showed concordant positive and negative results for anti-HCV, Murex Ag/Ab, and HCV RNA tests. In the HIV/HCV group, all 100 samples were positive for both anti-HCV and Murex Ag/Ab tests, whereas 88 patients (88%) were HCV RNA positive. In the uremia group, 14 (69.0%) of the 23 anti-HCV-positive patients were HCV RNA positive, whereas 14 (77.8%) of the 18 Murex Ag/Ab–positive patients were HCV RNA positive. None of anti-HCV-negative or Murex Ag/Ab–negative patients were HCV RNA positive. Based on the HCV RNA assay, the sensitivities for both anti-HCV and Murex Ag/Ab assays were 100%, whereas the specificities of these two assays were 89.7% and 95.4%, respectively. With good sensitivity and specificity, the Murex Ag/Ab assay could be a useful alternative diagnostic tool, especially in immunocompromised populations, such as patients with uremia or those infected with HIV.