Bay Area Reporter - December 15, 2005
Matthew S. Bajko, m.bajko@ebar.com

Once approved by both the city's Department of Public Health and Centers for Disease Control and Prevention officials, the new guidelines will require providers to immediately use a finger prick test on any clients who receive a positive result from the oral test. The CDC is expected to publish its recommendations in its Morbidity and Mortality Weekly Report Friday, December 16.

As with the oral test, the finger test provides results within 20 minutes and is more accurate than the oral test, health officials said. Currently, providers will do a blood draw on a client who receives a positive result from the oral test. The results are not known for at least a week, though, prolonging the emotional stress for clients who must spend seven days uncertain of their HIV status. And if the second test result is discordant with the first, it could be another two weeks before the client receives an accurate diagnosis.

"We are currently going through the process of getting approval to do two screenings up front. If the oral test is positive, we would follow that up immediately with a finger stick. If both tests are reactive then it is highly likely that the person is HIV-positive and we can say that to the client," said Teri Dowling, manager for HIV counseling and testing at the city's AIDS Office. "If the finger stick is negative then it's likely that the person is not HIV-positive because the finger stick is slightly more accurate than the oral test."

Health officials requested the procedural change after noticing a doubling in false positive test results this fall from those seen in the spring and summer. In May the city recorded four false positives, four again in June, two in July and four in August. Then in September the numbers doubled to nine cases; there were 12 cases in October and 11 cases in November.

In October, officials from the state, the CDC, and four executives from Orasure Technologies, the company that makes the OraQuick Advance HIV tests and has applied with the Food and Drug Administration to sell the test kits over the counter, met in San Francisco to visit the testing sites reporting the false positives and try to figure out why they had higher rates of discordant test results. Some speculation has centered on people carrying antibodies to hepatitis as the reason for the false positive results, but the cause still remains a mystery.

"Ultimately, the answer is we don't know," said Shelley Facente, the city's HIV rapid testing program coordinator. "No one has been able to figure out something conclusive."

What is known is that not all of the city's 14 testing sites using the oral test reported clusters of false positives. Out of the 49 false positives reported this year, two-thirds occurred with gay and bisexual men.

Dowling said that the city has confirmed that half of those people have been retested and are known to be negative, while the other half are suspected to be false positives but the city was unable to keep track of whether they were retested.

Despite the concern over the false positive results, Dowling stressed that health officials remain confident in the overall accuracy in using the oral tests. Since introducing the oral tests in January, 9,400 oral tests have been administered, with 250 of those being confirmed positives, 49 being false positives and the rest negatives. In its marketing materials, Orasure states studies found that 4 in 1,000 of its oral tests to be false positives.

City Clinic, which had used the oral rapid test for about a month and did not have any false positive results, decided to go with the finger stick tests instead, said Dowling. Although she added, "The oral rapid HIV test is a very valuable tool in identifying HIV. The test itself is 99 percent accurate."

Douglas Michels, Orasure's chief executive, said in a San Francisco Chronicle story Friday, December 9 that the company has not heard of similar problems with its test in other cities, including New York City.

"We do not have any reason to believe our product is not performing to specification,'' he said. "We have every confidence that the test is reliable and accurate.''

Michels added, "This doesn't mean that a site may report unusual results, but that is normal in the course of business with any kind of laboratory test.''

Contrary to Michels's claims, San Francisco is not alone in seeing unaccounted for spikes in false positive results from the oral tests. Health officials in Houston, Utah, Minnesota, and New York City have all reported concerns after seeing clusters of false positive results.

The company's response has upset at least one person who received a false positive result after being administered the oral test.

"My concern is not that this happened but the company saying San Francisco is the only place it is happening so it doesn't matter. It is almost like they are saying we are going to do what we want to with this test anyway, even if there was a problem with the test," said the man, who asked that his name not be used. "It was very emotionally difficult."

The man went in September to the AIDS Health Project to be tested for HIV to ease his mind after suffering from what he feared was a seroconversion flu. The clinician told him his test came back as a preliminary positive and proceeded to do a blood draw in order to confirm the result.

A week later the man returned and was told his test results were inconclusive. He then went to City Clinic for further testing, and after more blood work was done, learned he is negative. The experience has left him doubting if the oral tests should be sold over the counter, he said.

"I was afraid I was positive for a month," he said. "I don't really know if the kits should be sold. I literally could not walk home. I had to call through my cell phone to find a friend to come get me. I couldn't go home, I had to go to their house. For someone to get the news in their own house is pretty devastating. I am trusting the people who make these decisions weigh the risks."

He said he is glad with how the city and AHP have reacted. AHP dropped using the oral tests and is now using the finger stick tests.

"I want to be certain both of those organizations make sure the company takes it as seriously as they have and addresses it before they start selling these kits publicly," he said.

The FDA has just begun its review process of Orasure's application. Elliot Cowan, an FDA scientist who reviewed the oral test, told the New York Times that it was never meant to be an authoritative result but an indication that another test should be conducted. The Times quoted Cowan in a December 10 article as saying the FDA is "not dismissing" the false positive reports, adding, "but from the numbers I've seen, the test is performing pretty close to the way it is supposed to perform."

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