One-step HCV test demonstrates 99% specificity, 100% sensitivity

Ke-Qin Hu

A novel one-step hepatitis C virus antigens enzyme immunoassay showed 99% specificity and 100% sensitivity in differentiating resolved HCV from viremic HCV, according recent findings published in Hepatology.

“The present study introduced a novel, highly specific and sensitive HCV antigens enzyme immunoassay (HCV-Ags EIA) test that is well-correlated to HCV replication as determined by serum HCV RNA real-time polymerized chain reaction (RT-PCR),” Ke-Qin Hu, MD, and Wei Cui, MD, both in the division of hepatology at the University of California, Irvine School of Medicine, wrote. “Based on the literature, its sensitivity is superior to those reported for HCV core antigen (HCVcAg) assays. Additionally, our HCV-Ags EIA offers significantly improved specificity by excluding sample denaturation and provides a highly specific and reliable one-step test to screen and diagnose viremic HCV (V-HCV) infection.”

Current HCV diagnostics require two steps: an anti-HCV screening test and an HCV RNA RT-PCR to confirm viremic HCV. HCVcAg assays require only one step, but they have low sensitivity and specificity, according to the researchers.

Hu and Cui assessed the sensitivity and specificity of a novel one-step HCV-Ags EIA by using 365 serum specimens, 189 of which had viremic HCV. The assay works by detecting the presence of the HCV nonstructural proteins 3, 4b and 5a as well as HCV core antigen protein.

The researchers found that serum sample denaturation decreases test specificity, which was a novel finding. This suggests that denaturation should not be used in any HCV antigen assay. Using sample nondenaturation, the HCV-Ags EIA showed 99% specificity and 100% sensitivity compared with serum anti-HCV and HCV RT-PCR results. The lowest levels of detection were equivalent to serum HCV RNA levels between 150 and 250 IU per mL.

The researchers concluded that their novel assay can reliably differentiate viremic HCV from resolved HCV when using nondenaturation of serum samples.

“Sample nondenaturation is the only way to assure the feasibility to utilize HCV-Ags assays to specifically diagnose V-HCV infection,” the researchers wrote. “Additionally, eliminating sample denaturation will make this type of test more time-saving and simple.”

Hu and colleagues also presented findings from the HCV-Ags EIA assay at The Liver Meeting in 2015, suggesting that the one-step test was effective for screening and diagnosing HCV infection using urine samples. – by Will Offit

Disclosures: Hu reports serving on the speakers bureau for AbbVie, Gilead Sciences and Janssen, as well as being a consultant for DiligenMed Inc. Cui reports no relevant financial disclosures.

Ke-Qin Hu

A novel one-step hepatitis C virus antigens enzyme immunoassay showed 99% specificity and 100% sensitivity in differentiating resolved HCV from viremic HCV, according recent findings published in Hepatology.

“The present study introduced a novel, highly specific and sensitive HCV antigens enzyme immunoassay (HCV-Ags EIA) test that is well-correlated to HCV replication as determined by serum HCV RNA real-time polymerized chain reaction (RT-PCR),” Ke-Qin Hu, MD, and Wei Cui, MD, both in the division of hepatology at the University of California, Irvine School of Medicine, wrote. “Based on the literature, its sensitivity is superior to those reported for HCV core antigen (HCVcAg) assays. Additionally, our HCV-Ags EIA offers significantly improved specificity by excluding sample denaturation and provides a highly specific and reliable one-step test to screen and diagnose viremic HCV (V-HCV) infection.”

Current HCV diagnostics require two steps: an anti-HCV screening test and an HCV RNA RT-PCR to confirm viremic HCV. HCVcAg assays require only one step, but they have low sensitivity and specificity, according to the researchers.

Hu and Cui assessed the sensitivity and specificity of a novel one-step HCV-Ags EIA by using 365 serum specimens, 189 of which had viremic HCV. The assay works by detecting the presence of the HCV nonstructural proteins 3, 4b and 5a as well as HCV core antigen protein.

The researchers found that serum sample denaturation decreases test specificity, which was a novel finding. This suggests that denaturation should not be used in any HCV antigen assay. Using sample nondenaturation, the HCV-Ags EIA showed 99% specificity and 100% sensitivity compared with serum anti-HCV and HCV RT-PCR results. The lowest levels of detection were equivalent to serum HCV RNA levels between 150 and 250 IU per mL.

The researchers concluded that their novel assay can reliably differentiate viremic HCV from resolved HCV when using nondenaturation of serum samples.

“Sample nondenaturation is the only way to assure the feasibility to utilize HCV-Ags assays to specifically diagnose V-HCV infection,” the researchers wrote. “Additionally, eliminating sample denaturation will make this type of test more time-saving and simple.”

Hu and colleagues also presented findings from the HCV-Ags EIA assay at The Liver Meeting in 2015, suggesting that the one-step test was effective for screening and diagnosing HCV infection using urine samples. – by Will Offit

Disclosures: Hu reports serving on the speakers bureau for AbbVie, Gilead Sciences and Janssen, as well as being a consultant for DiligenMed Inc. Cui reports no relevant financial disclosures.