Newer, Less Expensive Tests Could Speed Up HCV Diagnosis

Tests for hepatitis C virus core antigen (HCVcAg) have high sensitivity and specificity and could replace nucleic acid testing (NAT) in the diagnosis of hepatitis C (HCV), according to the results of a recent study.1

In an effort to make diagnosis of HCV cost effective, an inexpensive HCV antibody screen is followed by a more expensive NAT for confirmation in those who test positive for HCV antibodies.
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“This two-step process presents a major obstacle to diagnosis and treatment because a significant proportion of patients either do not undergo testing or do not follow up after an initial positive screen,” according to the authors.

“A single-process diagnostic for chronic HCV infection could streamline the cascade of care in low- and middle-income countries where HCV is prevalent, but patients are often lost to follow-up.”2

To evaluate the accuracy of diagnosis with HCVcAg vs NAT, researchers conducted a meta-analysis of case-control, cross-sectional, cohort, or randomized trials that compared any of 5 available HCVcAg tests with an NAT reference.

Overall, sensitivity of the assays ranged from 59.5% to 93.4% and specificity of the assays ranged from 82.9% to 98.8%. Insufficient data were available to calculate the sensitivity and specificity of 2 of the 5 assays.

In 3 quantitative studies of 1 of the assays, HCVcAg correlated closely with HCV RNA levels greater than 3000 IU/mL.

“The HCVcAg assays with signal amplification have high sensitivity, high specificity, and good correlation with HCV RNA levels greater than 3000 IU/mL and have the potential to replace NAT in settings with high HCV prevalence,” the authors said.

—Michael Potts

References:

  1. Freiman JM, Tran TM, Schumacher SG, et al. Hepatitis C core antigen testing for diagnosis of hepatitis c virus infection: a systematic review and meta-analysis [published online June 21, 2016]. Ann Intern Med. doi:10.7326/M16-0065.
  2. Newer tests could cut hep C diagnosis steps in half  [press release]. Philadelphia, PA: American College of Physicians; June 20, 2016.