CDC dispatch: Confirmation of HIV Antibody Tests (re: False Positives)

There was a post recently about the number of false-positive HIV tests reported from the San Francisco Dept. of Health from oral fluid samples screened by OraQuick's Rapid HIV antibody test. Here's a brief dispatch from the CDC, distributed by the Morbidity and Mortality Weekly Report, addressing the issue. It's typically dry and data oriented, but I thought I'd pass it on as a follow-up for those interested. Their key point is that the rapid test is a screening tool and has to be confirmed with a subsequent confirmatory test.

Supplemental Testing for Confirmation of Reactive Oral Fluid Rapid HIV Antibody Tests

MMWR
December 16, 2005 / 54(Dispatch);1

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A reactive rapid HIV test result is considered preliminary and must be confirmed by supplemental testing (1). Some false positive rapid test results (i.e., reactive rapid test results followed by negative supplemental test results) are to be expected within the range of specificity for the device. However, in late 2005, HIV testing programs in multiple U.S. cities experienced apparent clusters of false-positive rapid HIV test results using oral fluid (but not whole blood) specimens. Counselors at these programs have expressed concern regarding the specificity and positive predictive value of the oral fluid rapid HIV test.

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CDC is actively working with FDA, state and local health officials, and the product manufacturer to investigate these reports, assess the test's current performance, and consider whether changes in testing protocols should be recommended or any other actions taken. In the meantime, current protocols for confirmation of reactive rapid HIV test results should continue to be followed (2). These protocols ensure that clients with reactive rapid test results receive accurate HIV test results after confirmation. HIV counselors returning reactive (preliminary positive) results from HIV rapid tests to clients should provide the same counseling message that is currently recommended (3), regardless of whether the reactive test result was obtained using oral fluid or whole blood.

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http://www.cdc.gov/mmwr/preview/mmwrhtml/mm54d1216a1.htm

ed for clarity