HIV Kit Giving Errant Results

An oral HIV test that uses a swab to quickly detect the virus that causes AIDS provided false positive readings for about a quarter of the people it showed to be infected, the San Francisco Department of Public Health said Friday.

Subsequent blood tests showed that 47 people who tested positive using OraQuick Advance HIV tests in 2005 were not infected, said Jeffrey Klausner, director of the department’s sexually transmitted disease prevention and control services.

It was not known whether any of the tests falsely indicated that someone was free of HIV when, in fact, that person was infected, he said.

Many of those who test negative do not have subsequent blood tests.

Klausner and Deanne Sykes, a research scientist with the California Department of Health Services’ Office of AIDS, said there had been other false positives in Ohio and New York state.

“There have been little clusters of them there,” Sykes said. “A few of them appeared, and then they went away.”

What is causing the erroneous results with the oral tests “is the million-dollar question,” she said.

“The tests are reacting to something that’s not HIV,” she said. “Nobody knows what it is.”

Sykes said her office had ruled out procedural errors in administering the tests.

Klausner said there had been some question about expiration dates on the test kits, and he believed the problem was related to the kits themselves.

But Douglas Michels, chief executive of OraSure Technologies Inc., the Bethlehem, Pa., company that developed the kits, said they are reliable and accurate.

“We do not have any reason to believe our product is not performing to specification,” he said.

The oral HIV tests were approved by the federal Food and Drug Administration in March 2004.

Health workers simply swipe a treated swab along the gums of the person being tested and insert the swab into a testing device for immediate results.

The standard test for HIV takes a minimum of five hours to process and sometimes as long as overnight.

Because those tests often are sent to laboratories, where they are processed in batches, results sometimes are not available for days or even weeks.

The oral test is the second rapid HIV test to be put on the market.

The other one uses a spot of blood to get a reading.

Both rapid tests are made by OraSure.

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Associated Press contributed to this report.