Point-of-Care Test for Hepatitis C
Point-of-care testing for hepatitis C is a newly developed rapid test that can be performed in a clinic, emergency department, church, or home without the need for a lab technician or machine, providing results in 20 minutes. This test was compared with standard laboratory methods (enzyme immunoassay, recombinant immunoblot assay, and PCR) to determine sensitivity and specificity. Specimens were obtained from 2206 volunteers who were considered at risk for HCV infection and had a 34% positive rate with the standard test.
The results indicate that any of the following specimens could be used: serum, plasma, fingerstick blood, venipuncture, or saliva. Results compared with the standard alternative tests were 99.7%-99.9% for sensitivity and 99.6%-99.9% for specificity. The exception was a slight decrease in sensitivity with saliva, which showed 98.1% sensitivity and 99.6% specificity. The investigators concluded that this technique shows performance results comparable to standardized tests and consequently should be considered adequate for FDA approval.
Why Is This a Game Changer?
Identifying people with hepatitis C infection is of great importance; a challenge comparable to that of HIV detection in the sense that many are not aware that they are infected. Treatment of both conditions would result in substantial health benefits to the individual and also important public health benefits in reducing or eliminating the risk for transmission to other individuals. The challenge of finding patients with HIV is likely to be repeated for HCV. The rapid test for HIV has revolutionized the disease in most of the world, and the report card after several years of experience shows that the rapid test for HIV read by minimally trained personnel is nearly flawless.
This report calls attention to the potential benefits of point-of-care testing in the 21st century, as the laboratory has become increasingly distant from the bed or the clinic. With point-of-care testing, the results are available on site, usually within 20 minutes, and performance characteristics are close to or equal to those of conventional testing. Of importance, the preliminary results or definitive diagnosis can be made while the patient is in the clinic or the emergency department.
Point-of-care testing has evolved rapidly, with emphasis on the ASSURED criteria, which stands for Affordable, Sensitive, Specific, User-friendly (minimal training requirement), Rapid (< 20 minutes), Equipment (no expensive equipment) and Delivered (FDA-cleared).
What Does This Mean to the Practitioner?
Who can do these tests? It depends on the Clinical Laboratory Improvement Amendments (CLIA) waiver, an FDA decision. If the test (such as the rapid HIV test) is CLIA-waived, a person working in your clinic or emergency room could be certified by the laboratory director as "CLIA certified," permitting this person to interpret the test at the site of care with no requirement for specimen transport to the laboratory. CLIA-waived tests have the potential advantage of 24-hour service. In general, the only skill needed to perform these tests is the ability to recognize a red line. Point-of-care molecular tests may be more expensive and require a licensed laboratory technician.
A concern about point-of-care tests is that because they are not conducted in the laboratory, the results either do not get into the medical record system; or if they do, they are typically not included with other laboratory test results so they may be difficult to find.
Point-of-care tests are defined by the short time required for results -- usually within 1-2 hours.
The ultimate goal is for these tests to be available commercially to consumers and sold in drugstores to facilitate self diagnosis, improve disease detection, and reduce cost.
Particularly attractive has been the use of these tests for detection of sexually transmitted infections in adolescents who have reservations about addressing these concerns to parents or medical providers and have established a strong track record for self diagnosis using this technology. It is likely that physicians in the near future will encounter more patients who present with either preliminary or definitive test results. Healthcare professionals will worry about quality assurance with self testing by consumers, but it certainly has worked well with pregnancy tests, and the initial testing for sexually transmitted infections is very promising.
Medscape Infectious Diseases © 2011
Cite this: John Bartlett's Game Changers in Infectious Disease: 2011 - Medscape - Oct 26, 2011.