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HCV core antigen assays show potential to replace nucleic acid testing

Recent findings published in the Annals of Internal Medicine showed that HCV core antigen assays could potentially replace the currently used nucleic acid testing in areas with high HCV prevalence.

“This systematic review showed that several [HCV core antigen (HCVcAg)] assays are highly sensitive (>90%) and specific (>98%),” J. Morgan Freiman, MD, at Boston Medical Center, and colleagues wrote. “Although even tests with the highest performance are not as sensitive as [nucleic acid testing (NAT)], well-performing HCVcAg tests with an analytic sensitivity reaching into the femtomolar range (equal to 3000 IU/mL) could replace NAT for HCV detection, particularly if a lower cost per test allows more patients to be served.”

Currently, HCV detection requires a positive antibody screen and a confirming nucleic acid test (NAT), the researchers wrote. Although this 2-step algorithm is cost-effective, the process is often not feasible in low- to middle-income countries, wherefewer than 1% of those infected with HCV are aware of their infection.

To evaluate a potentially better test, Freiman and colleagues performed a systematic review and meta-analysis of 44 studies that assessed any of the five HCVcAg assays.

They found that Abbott ARCHITECT HCVcAg had a sensitivity of 93.4% (95%CI, 90.1-96.4) and a specificity of 98.8% (95% CI, 97.4-99.5). For Ortho ELISA HCVcAg, these sensitivity and specificity were 93.2% (95% CI, 81.6-97.7) and 99.2% (95% CI 87.9-100). For Hunan Jynda Bioengineering Group, they were 59.5% (95% CI, 46.0-71.7) and 82.9% (95% CI, 58.6-94.3). There was insufficient data for the other two HCVcAg tests: Fujirebio Lumipulse Ortho and Eiken Lumispot. The researchers also found that Abbott ARCHITECT correlated closely with HCV RNA levels greater than 3000 IU/mL.

“This systematic review concludes that a well-performing HCVcAg test can achieve similar diagnostic accuracy to NAT for identification of active HCV infection when the viral load exceeds 3000 IU/mL,” the researchers wrote. “Therefore, HCVcAg should be explored for [point of care] testing to increase the number of patients diagnosed and streamline the HCV cascade of care.” – by Will Offit

Disclosures: Freiman reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.