The New York Times - December 10, 2005
Denise Grady

The test, called the OraQuick Advance H.I.V. test, is the same one the Food and Drug Administration has said it will consider approving for sale to the public for home use without a prescription.

But officials in the two cities and at the drug agency also emphasized that the test, which requires a mouth swab instead of a blood sample, should not be abandoned, because its convenience made it a valuable tool in fighting AIDS.

Rather, they said, the problem needs to be investigated, and clinics and patients need to be aware that a positive result must be confirmed by another type of test.

Difficulties with the test were first reported yesterday in The San Francisco Chronicle.

In New York, Dr. Susan Blank, an assistant health commissioner, said that city clinics performed 3,600 to 3,700 tests for the virus, H.I.V., each month, largely using OraQuick, and until recently they had about five false positives a month, a rate well within the maker's prediction.

But in November, Dr. Blank said, the number shot up to 30, which was cause for concern.

"We have made several lot switches to make sure we have the most recent specimen kits," Dr. Blank said, adding that the city laboratories had also reviewed their own procedures to make sure they were using the test kits correctly.

She added, "We have spoken with the company several times and written to the company to try to resolve the problem, and have taken steps to inform the F.D.A."

The city also informed the Centers for Disease Control and Prevention, Dr. Blank said. Rapid testing "remains an important tool in stopping the spread of H.I.V.," she said, adding, "I think we need to be careful that we don't throw out the baby with the bath water."

In San Francisco, Teri Dowling, manager of H.I.V. counseling and testing for the public health department, said the number of false positives there seemed to rise sharply in May. In 2005, 9,400 tests were done, and 250 were positive. Of those, 49 appeared to be false positives, though not all have yet been confirmed.

Ms. Dowling said her department was also working with the company, OraSure Technologies in Bethlehem, Pa., and the disease agency to try to find out what was going on. In the meantime, she said, her department expected to alter its testing process.

She said that it would continue to use OraQuick, but that if a test was positive, a rapid blood test, which is more accurate, would be done immediately. Additional tests would also be done, she said.

Dr. Elliot Cowan, an F.D.A. scientist who has reviewed the test, said a positive result was never meant to be definitive, but was an indication that another, more accurate test should be done.

Still, Dr. Cowan said of the current problem, "we're not dismissing it."

Dr. Cowan said the agency had contacted company officials and was working with them to determine if there was a problem. "But from the numbers I've seen," he said, "the test is performing pretty close to the way it is supposed to perform."

Douglas A. Michels, president and chief executive of OraSure, said that over all the test was more than 99 percent accurate. In the last year, the company received complaints of only 107 false positives out of 28,436 tests, Mr. Michels said.
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