Novel Test Allows for One-Step Diagnosis of HCV Infection

Although health professional practice guidelines advocate screening for HCV infection, recent studies indicated a significant deficit in screening and diagnosis of HCV infection.

Scientists at the University of California, Irvine, School of Medicine (Orange, CA, USA) developed a novel HCV antigens enzyme immunoassay for HCV core antigen (HCV-Ags EIA) and assessed its sensitivity, specificity, and utility for one-step diagnosis of viremic HCV (V-HCV) infection using 365 serum specimens, including 176 without, and 189 with V-HCV infection. They confirmed presence of HCV non-structural protein 3 (NS3), NS4b, and NS5a proteins besides HCVcAg during HCV infection, and developed a novel HCV-Ags EIA via simultaneous detection of all these 4 HCV proteins.

The study demonstrated that serum sample denaturation decreases the test specificity due to release of HCV-Ags sequestered in HCV-immune complexes, and should not be used in any HCV-Ags, including all the current HCVcAg assays. On the other hand, using sample non-denaturation, the HCV-Ags EIA results showed 99% specificity and 100% sensitivity compared to serum anti-HCV and HCV RNA RT-PCR results. Using serum sample dilution, and non-denaturation, the lowest limits of detection of the HCV-Ags EIA were equivalent to serum HCV RNA levels of approximate 150-250 IU/mL.

The authors concluded that the highly specific and sensitive HCV-Ags EIA they developed has the lowest limit of detection equivalent to serum HCV RNA levels of 150-250 IU/mL. Using non-denaturation of serum samples, our HCV-Ags EIA reliably differentiated V-HCV infection from resolved HCV infection, accomplishes screening and diagnosis of V-HCV infection in one step.

Ke-Qin Hu, MD, director of hepatology services and senior author of the study said, “Our novel HCV antigen test system has significantly improved sensitivity and specificity over current tests. Importantly, for the first time, we can use urine specimens for one-step screening and diagnosing of HCV infection. Finding a more convenient, easy-to-use and cost-effective screening alternative is imperative, because HCV is significantly under-screened and under-diagnosed.” The study was published on June 6, 2016, in the journal Hepatology.

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University of California, Irvine, School of Medicine