Changes Planned in Use of Oral HIV Test;
Blood to Be Checked Quickly to Confirm Any Positive Results
Acting on news of an unusually high number of false positives with a
rapid-result oral HIV test in two cities, federal health authorities soon will
issue new guidelines for its use. San Francisco public health clinics have
recorded 49 false positives with the OraQuick Advance HIV test since May. New
York clinics logged 10 false positives in October and 30 in November, San
Francisco officials said.
CDC plans to advise that clinics immediately follow up positive oral test
results by performing a rapid-result blood test, said Dr. Bernard Branson,
associate director for laboratory diagnostics at the agency. "What we intend to
suggest is that if someone is tested with oral fluid and is positive, that
person, if it is possible at the clinic, should get a finger-stick test." The
same OraQuick test is licensed to test oral fluid, blood droplets or blood drawn
into a test tube. The blood-testing method also delivers results in 20 minutes;
however, no comparable reliability issues have been raised for it. If the second
test's result is negative, the patient would still need to undergo the more
sophisticated Western Blot lab tests. Results for this can take a week, but in
the meantime, the patient could be sent home with the assurance that the initial
oral test's positive result was likely wrong.
CDC will probably issue the advisory in the next edition of its Morbidity and
Mortality Weekly Report, Branson said.
Large-scale monitoring of the test showed an accuracy rate of 99.6 percent,
which is comparable to the best blood tests available. But Branson said he is
"not comfortable" with the clusters of false positives reported in San Francisco
and New York.
Douglas Michels, CEO of test maker Orasure Technologies, said despite the San
Francisco false positives, the test's performance has been within guidelines set
by the Food and Drug Administration. The agency approved the test for
professional use in March 2004 and is considering an application for
over-the-counter sales. Michels declined to comment on the reported New York
numbers and said he had not discussed with CDC a change in the recommendations
for the test's use.