Rapid hepatitis C tests: better than the gold standard?

Measures and Metrics for Feasibility of Proof-of-Concept Studies With Human Immunodeficiency Virus Rapid Point-of-Care Technologies: The Evidence and the Framework

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Objective

Pilot (feasibility) studies form a vast majority of diagnostic studies with point-of-care technologies but often lack use of clear measures/metrics and a consistent framework for reporting and evaluation. To fill this gap, we systematically reviewed data to (a) catalog feasibility measures/metrics and (b) propose a framework.

Methods

For the period January 2000 to March 2014, 2 reviewers searched 4 databases (MEDLINE, EMBASE, CINAHL, Scopus), retrieved 1441 citations, and abstracted data from 81 studies. We observed 2 major categories of measures, that is, implementation centered and patient centered, and 4 subcategories of measures, that is, feasibility, acceptability, preference, and patient experience. We defined and delineated metrics and measures for a feasibility framework. We documented impact measures for a comparison.

Findings

We observed heterogeneity in reporting of metrics as well as misclassification and misuse of metrics within measures. Although we observed poorly defined measures and metrics for feasibility, preference, and patient experience, in contrast, acceptability measure was the best defined. For example, within feasibility, metrics such as consent, completion, new infection, linkage rates, and turnaround times were misclassified and reported. Similarly, patient experience was variously reported as test convenience, comfort, pain, and/or satisfaction. In contrast, within impact measures, all the metrics were well documented, thus serving as a good baseline comparator. With our framework, we classified, delineated, and defined quantitative measures and metrics for feasibility.

Conclusions

Our framework, with its defined measures/metrics, could reduce misclassification and improve the overall quality of reporting for monitoring and evaluation of rapid point-of-care technology strategies and their context-driven optimization.

[Which place for point-of-care screening tests in the diagnosis of hepatitis C infection among drug users?]

Hepatitis C is a severe disease, which often evolves into chronicity and for which there is no vaccine available. Therefore its screening is essential, especially among drug users who are the main reservoir of the hepatitis C virus (HCV). Current guidelines for screening are based on the detection of total anti-HCV antibodies (Ab) by means of third generation EIA. This test is performed in a laboratory from a venous sample. Alternative methods have been recently developed, including point-of-care tests (POCT) that offer many advantages. Their excellent diagnostic performance, their quick results and their ease of use by a large number of professionals are arguments in favor of widespread use of these tests. The expected benefits of the use of POCT are individual (better knowledge of HCV status, better access to care and treatment) but also collective (reduction of morbidity and mortality related to HCV and its cost in terms of public health) Because of their clinical interest, POCT should be refunded as well as the currently recommended screening test. In order to optimize their ease of use, POCT use should be integrated into an organized screening and hepatology follow-up system.

Comparison of Rapid Point-of-Care Tests for Detection of Antibodies to Hepatitis C Virus

OraSure had the highest sensitivity at 92.7% followed closely by Chembio's three blood tests. False results were associated with HIV, and hepatitis B core antibody. The OraSure and Chembio blood tests have good performance characteristics.

Background. Hepatitis C is one of the most prevalent blood-borne diseases in the United States. Despite the benefits of early screening, among 3.2 million Americans who are infected with hepatitis C virus (HCV), 50%–70% are unaware of their infection status.

Methods. Data were collected between 2011 and 2014, from 1048 clients who were in the following groups: (1) injection drug users, (2) women at sexual risk, (3) gay and bisexual men, and (4) transgender individuals. The sensitivity and specificity of point-of-care tests included (1) the MedMira rapid human immunodeficiency virus (HIV)/HCV antibody test, (2) MedMira hepatitis B (HBV)/HIV/HCV antibody test, (3) Chembio HCV Screen Assay used with both whole blood and (4) oral specimens, (5) Chembio HIV-HCV Assay also used with both whole blood and (6) oral specimens, (7) Chembio HIV-HCV-Syphilis Assay, and (8) OraSure HCV Rapid Antibody Test used with whole blood. The gold standard for the HCV tests were HCV enzyme immunoassay (EIA) 2.0.

Results. OraSure had the highest sensitivity at 92.7% (95% confidence interval [CI] = 88.8%–96.5%) followed closely by Chembio's 3 blood tests at 92.1% (95% CI = 87.7%–96.4%), 91.5% (95% CI = 87.2%–95.7%), and 92.3% (95% CI = 88.4%–96.2%). The sensitivities of MedMira HIV/HCV and MedMira HIV/HCV/HBV tests were the lowest, at 79.1% (95% CI = 72.6%–85.5%), and 81.5% (95% CI = 75.2%–87.8%), respectively. Specificity for the OraSure was 99.8% (95% CI = 99.4%–100%); specificity for the Chembio blood tests was 99.2% (95% CI = 98.6%–99.9%), 99.4% (95% CI = 98.8%–99.9%), and 99.3% (95% CI = 98.8%–99.9%); and specificity for the MedMira was100% and 100%. False-negative results were associated with HIV and hepatitis B core antibody serostatus.

Conclusions. The OraSure and Chembio blood tests (including those multiplexed with HIV and syphilis) appear to good performance characteristics. This study has identified potential limitations of rapid testing in those testing positive for HIV and HBcAb. There should be discussion of updates to the 2013 CDC guidance.

Tools for the diagnosis of hepatitis C virus infection and hepatic fibrosis staging

Hepatitis C virus (HCV) infection represents a major public health issue. Hepatitis C can be cured by therapy, but many infected individuals are unaware of their status. Effective HCV screening, fast diagnosis and characterization, and hepatic fibrosis staging are highly relevant for controlling transmission, treating infected patients and, consequently, avoiding end-stage liver disease. Exposure to HCV can be determined with high sensitivity and specificity with currently available third generation serology assays. Additionally, the use of point-of-care tests can increase HCV screening opportunities. However, active HCV infection must be confirmed by direct diagnosis methods. Additionally, HCV genotyping is required prior to starting any treatment. Increasingly, high-volume clinical laboratories use different types of automated platforms, which have simplified sample processing, reduced hands-on-time, minimized contamination risks and human error and ensured full traceability of results. Significant advances have also been made in the field of fibrosis stage assessment with the development of non-invasive methods, such as imaging techniques and serum-based tests. However, no single test is currently available that is able to completely replace liver biopsy. This review focuses on approved commercial tools used to diagnose HCV infection and the recommended hepatic fibrosis staging tests.

Diagnostic Performance of Two Point-of-Care Tests for Anti-HCV Detection

BACKGROUND

Besides the great importance of the issue in terms of public health, there is a lack of studies evaluating the performance of several of the currently used point of care tests (POCTs) for the detection of anti-HCV.

OBJECTIVES

To investigate the performance of two POCTs for anti-HCV detection and to assess the impact of the reading time on diagnostic performance.

PATIENTS AND METHODS

A total of 307 subjects were divided into three groups (1- HCV infected; 2- other chronic liver diseases; and 3- controls). The POCTs HCV Rapid Test Bioeasy® and Imuno-Rapido HCV® were read at 3, 5, 10, 15, 20 and 30 minutes. The sensitivity and specificity of the POCTs were calculated in relation to anti-HCV detection by chemiluminescence.

RESULTS

Valid results were obtained for all tests. When compared to the chemiluminescence, both tests showed sensitivity of 97.1% and specificity of 100%. No changes in the sensitivity or specificity of the tests were observed at different reading times and when patients with other chronic liver diseases were evaluated as a control group.

CONCLUSIONS

The POCTs evaluated in this study showed high sensitivity and specificity, with no change in the performance after the third minute of reading.