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More Sites Drop Oral HIV Test

A spate of false positives prompts health centers in New York and California to halt use of the product as federal agencies begin inquiries.

December 20, 2005|Rong-Gong Lin II and Juliet Chung | Times Staff Writers

A recent surge in false positive results produced by a much-heralded oral HIV test has caused at least six testing sites in Los Angeles, San Francisco and New York to shelve the test and prompted an inquiry by federal health agencies.

In the last month, the L.A. Gay & Lesbian Center, San Francisco's largest HIV testing center, the New York City health department and other facilities have stopped using the rapid test, which gives results in 20 minutes from a saliva swab.

The test, OraQuick Advance, has become an important tool at HIV testing sites in the last year, particularly at clinics and outreach settings targeting people at high risk for the virus. It is painless and requires no blood sample, which makes it easier to administer and popular with clients.

Officials at the U.S. Food and Drug Administration and the national Centers for Disease Control and Prevention are investigating the complaints. But they said there is no reason at this point to pull the test off the market. CDC data collected earlier this year showed that the oral test was 99.8% accurate for people not infected with the virus.

More recent test results from some large health clinics have seen rates as low as 99.1%. The difference may be small, but when testing large groups of people, the number actually affected can be significant.

For example, New York health officials saw the number of false positives jump in November to 35 out of 3,754 tests of people not infected, according to the Centers for Disease Control.

"Some false positive results are expected with any HIV screening test," said FDA spokeswoman Kimberly Rawlings. "For this reason, additional testing is always needed to confirm true positive results."

Rawlings added that the agency would take "further corrective action, if needed," based on the results of the inquiry.

The test's manufacturer, OraSure Technologies of Bethlehem, Pa., said it is working closely with healthcare and government officials to investigate the complaints. OraSure officials met with the L.A. Gay & Lesbian Center and the Los Angeles County health department Monday.

"We're going to work aggressively ... to get to the bottom of this," said Doug Michels, company president.

The oral test received FDA approval last year amid great fanfare. It was the first rapid test to use saliva, instead of blood, to rapidly screen for HIV. Health officials hoped it would make it easier to get more people tested for HIV and help curtail the spread of the virus.

The same kit can also utilize a small blood sample, from a pricked finger, to get an HIV result in 20 minutes. A version of the rapid blood test has been available since 2002.

Only the saliva test is suspected of having abnormally high false positives.

"Patients like it," said Dr. Susan Blank, an assistant health commissioner in New York City. She credited the saliva test with attracting an estimated 6,000 more people to get tested for the virus this year.

The Centers for Disease Control spent $2.3 million last year to purchase kits and distribute them nationwide. The center specifically mentions OraSure's tests in its outreach effort to promote rapid HIV testing.

Before rapid tests came on the market, it often took a week to receive results from an HIV test, and many people never retrieved their results.

The oral test became so popular at certain HIV testing sites that some agencies in New York and California used it exclusively for their clients' preliminary tests.

Testing centers began to notice the increase in false positive results in the last few months. After New York City health officials saw their numbers surge last month, they halted use of the oral test Dec. 2.

The city of San Francisco saw an uptick in false positives since February, reporting 47 out of about 7,800 oral tests. During that period, 175 tests were confirmed positive.

The false positives were detected during standard follow-up laboratory tests, whose results come in about a week after the preliminary rapid oral test. Both the New York City health department and the UCSF AIDS Health Project, which also dropped the test, looked carefully at how it was administered by employees and found no problems.

"It was so excruciating for our clients and for our staff to be getting these results," not knowing whether they were accurate, said Barbara Adler, an HIV testing program manager at the health project, San Francisco's largest testing center.

The center had used the oral rapid tests between April and mid-November, recording 31 false positives and 40 confirmed positives. The center tests about 300 people a month.

Since the center shifted to the rapid blood test made by OraSure, no false positives have occurred, Adler said.

Three other smaller HIV testing sites in San Francisco have also switched to the rapid blood test, said Shelley Facente, who coordinates HIV rapid testing for the public health department.

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