Rapid diagnostic and point-of-care tests for hepatitis C virus are accurate enough to be used in first-line HCV screening worldwide, according to results from the first systematic review of evidence on such tests.
Blood-based point-of-care tests (POCTs) had better sensitivity and specificity overall than did blood-based rapid diagnostic tests (RDTs), Sushmita Shivkumar of McGill University, Montreal, Quebec, and her colleagues reported Oct. 15 in Annals of Internal Medicine.
Courtesy US. Dept of Veterans Affairs
By being fast, accurate, and cheaper than conventional tests, the rapid diagnostic and point-of-care tests offer "great potential for expanded first-line screening for hepatitis C infection," the investigators stated.
POCTs do not require sample processing or refrigeration, and have a shelf life of 6 months or more. Rapid diagnostic tests, or RDTs, require refrigeration and sample processing. Manufactured by a variety of firms under various marketing names, all the tests can detect HCV infection in under 30 minutes, with many taking less than 5 minutes, according to the investigators, who conducted a meta-analysis of 18 studies evaluating the accuracy of one or more RDT or POCT, compared with standard assays (Ann. Intern. Med. 2012;157:558-566).
Ms. Shivkumar and her colleagues found blood-based POCTs (using serum, plasma, or whole blood) to be the most accurate of the tests evaluated in the included studies, showing 98.9% sensitivity with a 95% confidence interval [CI] of 94.5% to 99.8% for whole blood and 96.8% to 99.6% for serum or plasma). RDTs of serum or plasma had 98.4% sensitivity (95% CI 88.9% to 99.8%). Specificity was highest in POCTs of serum or plasma at 99.7% (95% CI, 99.3% to 99.9%), followed by POCTs of whole blood at 99.5% (95% CI, 97.5% to 99.9%), RDTs of serum or plasma at 98.6% (95% CI, 94.9% to 99.6%). POCTs for oral fluids had a sensitivity of 97.1% (95% CI, 94.7% to 98.4%) and specificity of 98.2% (95% CI, 92.2% to 99.6%).
POCTs and RDTs cannot distinguish between acute and chronic HCV infections, which is one of the reasons that public health organizations continue to favor conventional assays. The Food and Drug Administration currently approves the use of a single POCT for HCV, and for use only in nontraditional settings; in the United Kingdom and Canada such tests have not yet been approved.
However, by being fast, accurate, and cheaper than conventional tests, the rapid diagnostic and point-of-care tests offer "great potential for expanded first-line screening for hepatitis C infection and demonstrate the utility of blood-based singleton POCTs and of multiplex POCTs designed to provide integrated HIV and HCV screening of at-risk populations," Ms. Shivkumar and her associates wrote in their analysis. "Their rapid turnaround time limits loss to follow-up and facilitates early linkages."
The authors also concluded that their findings showed that the rapid and point-of-care tests could play a "substantial role" in expanded global screening initiatives for HCV.
The blood-based POCTs, besides being the most accurate, have the advantage of not requiring refrigeration, the investigators wrote. This feature is key in developing countries in Africa and Asia, where prevalence of HCV infection is highest.
Ms. Shivkumar and her colleagues noted several weaknesses in their meta-analysis, mostly related to the quality of studies included. Only three of the studies they evaluated were blinded, while four received industry funding; the conventional assays used as reference varied in the studies, and HCV genotype information was not collected in most.
The study was supported by grants from the Canadian Institutes of Health Research. None of the authors declared conflicts of interest.