Outcomes and costs of single-step hepatitis C testing in primary care, Birmingham, United Kingdom

In UK laboratories, the diagnostic algorithm for chronic hepatitis C (HCV) infection commonly requires two serological assays to confirm anti-HCV-antibody positivity in a serum sample followed by HCV RNA detection in a second whole-blood sample (two-step testing algorithm). A single-step algorithm (both anti-HCV antibodies and RNA tested on an initial serum specimen) has been advocated to reduce attrition rates from the care pathway.

To investigate the feasibility, clinical impact and relative costs of switching from a two-step to single-step testing algorithm in the laboratory, a pilot study on unselected primary care requests was undertaken.

All primary care patients tested for HCV infection from December 2013 to April 2016 were included. The single-step testing algorithm was introduced in March 2015. Before this, the two-step algorithm was used. Patients were followed up until August 2016.

RNA quantitation in plasma was within one log of serum values for 21 paired samples. Although all patients in the single-step algorithm received an RNA test, only 70% completed the two-step testing algorithm; differences in referral rates to specialist care was due to 30% of HCV antibody-positive patients in the two-step algorithm not having follow-up whole-blood sampling for HCV RNA testing. Costs per new diagnosis and new diagnosis referred to specialist care were lower in single-step testing by £94.32 and £144.25, respectively.

This study provides further evidence that a single-step testing algorithm, as recommended in the UK Standards for Microbiology Investigation, works in practice and should be the standard of care for screening for chronic HCV.