A population-based screening for hepatitis C antibodies and active infection using a point-of-care test in a low prevalence area

Background

Data on the true prevalence of hepatitis C virus (HCV) infection in the general population is essential. We evaluated a program implementing free universal HCV screening using a non-invasive point-of-care test (POCT) (OraQuick-HCV rapid test) in oral fluid in an urban area in Valencia, South-Eastern Spain.

Methods

A cross-sectional study was performed during 2015–2017. Free HCV screening was offered by regular mail to 11,500 individuals aged 18 and over, randomly selected from all census residents in the Health Department. All responding participants filled in a questionnaire about HCV infection risk factors and were tested in their tertiary Hospital. In those with a positive POCT, results were confirmed by enzyme-immunoassay and HCV-RNA.

Results

1,206 persons agreed to participate (response rate: 11.16%). HCV antibodies were detected in 19 (1.60%) cases (age-sex standardized rate: 1.31%; 95%CI: 0.82–2.07), but only 8 showed positive HCV-RNA (age-sex standardized rate: 0.56%; 95%CI: 0.28–1.14). The majority (89%) of the cases were born before 1965 and 74% had at least one known risk factor for HCV infection. All anti-HCV positive individuals were already aware of their infection, and no undiagnosed cases were detected. The performance of the POCT was excellent for detecting active infection.

Conclusions

These preliminary data suggest that HCV population screening with a POCT is feasible but, in our setting, mailing recruiting is not effective (11% response rate). The low prevalence of HCV antibodies and active infection in the participant population (with no new diagnoses made) suggests that, in our setting, underdiagnosis may be uncommon.

Performance of the OraQuick Hepatitis C virus antibody test in oral fluid and fingerstick blood before and after treatment-induced viral clearance

BACKGROUND

A reliable population screening strategy for hepatitis C virus (HCV) infection may be based in easy-to-use point-of-care (POC) tests for HCV antibodies, but validation data is needed before their potential widespread use in primary care or outreach practice. Besides, the sensitivity of these POC tests in patients with spontaneous or treatment-induced viral clearance is unknown.

OBJECTIVES

To test the performance of a non-invasive POC anti-HCV test (OraQuick HCV rapid test) in oral mucosal transudate (OMT) and fingerstick blood from patients with known anti-HCV serostatus and with or without active viremia (after treatment-induced clearance).

STUDY DESIGN

A risk factor questionnaire was collected from 317 consecutive patients (anti-HCV positive/HCV-RNA positive n = 107; anti-HCV positive/HCV-RNA negative after antiviral treatment n = 107; anti-HCV negative with other liver diseases n = 109) before performing the OraQuick HCV rapid test in OMT (n = 317) and fingerstick blood (n = 251). We calculated the sensitivity and specificity of the test by using anti-HCV serostatus as the reference gold-standard.

RESULTS

Among all anti-HCV seropositive patients, the clinical sensitivity and specificity of the OraQuick HCV rapid test in OMT was 89.9% and 100%, respectively. In fingerstick blood, the sensitivity improved to 98.8%. The sensitivity was higher in OMT (97.2%) in anti-HCV seropositive patients who were viremic as compared to that in non-viremic individuals (82.2%). In contrast, there were no significant differences in sensitivity between viremic and non-viremic individuals when testing fingerstick blood. Finally, extension of the read time to 40 min enhanced the sensitivity, especially in OMT (up to 94.7%) and in the subgroup of non-viremic, anti-HCV-positive patients (up to 90.1%).

CONCLUSIONS

The OraQuick HCV rapid test in OMT has a high sensitivity and specificity for detecting active HCV infection that decreases substantially in anti-HCV positive/HCV-RNA negative patients with treatment-induced viral clearance. For these individuals, extension of read times and testing fingerstick blood showed improved sensitivity.