Health officials in New York City recently confirmed that public STD clinics there stopped using OraQuick Advance Rapid HIV 1/2 test kits to test oral fluid after the tests returned a higher proportion of false HIV-positive results. The rate of false positives reached as high as 1.1 percent over the past eight months, and the 10 clinics changed their testing procedures on May 27, said Susan Blank, director of the city's Bureau of STD Control.
"So far, false positives have not been linked to handling, storage conditions, lot numbers, clinic sites, and test operators," said Blank. The city used 60,000 of the kits one year ago.
The kits are performing better elsewhere, said Ron Ticho, the spokesperson for OraQuick's maker, Orasure Technologies Inc.
"What's happening in New York appears to be a slight aberration," Ticho said. "Performance results may fall slightly outside the expected range for a short period of time. That's expected."
Orasure is working with CDC and city officials to study the problem. CDC is also investigating whether health officials in other cities have noticed similarly high rates of false positive results, which might needlessly worry patients, said Bernard Branson, associate director of laboratory diagnostics for CDC's Division of HIV/AIDS Prevention.
In 2004 and 2005, elevated false positive rates for OraQuick were seen by New York, San Francisco, Minnesota, and Utah health departments. At the time, the New York City decided to confirm positive results based on oral fluid by a second rapid OraQuick test using a blood sample. Health workers were advised to tell patients whose blood-based test came back negative that they should view the results as inconclusive until confirmed by a third, genetic PCR test, said Blank.
A report on the issue, "False-Positive Oral Fluid Rapid HIV Tests - 2005-2008," was published as an early release in Morbidity and Mortality Weekly Report (2008;57:1-5).
06/16/08
NEW YORK: Orasure’s Oral HIV Test Has Too Many False Positives
Source: Bloomberg:: John Lauerman; Courtesy of the CDC National Center for HIV, STD, and TB Prevention