OraSure AIDS Test Has High Rate of Error, Report Says (Update1)
By John Lauerman
Sept. 3 (Bloomberg) -- OraSure Technologies Inc.'s OraQuick screen for the AIDS virus, the only rapid test licensed to scan both oral fluids and blood for HIV, was 10 times less accurate than described in the product's label, a Seattle report found.
In 5,460 tests, OraQuick failed to spot at least 8 percent of 133 people found to have HIV infection with a comparable diagnostic, said Bob Wood, director of the HIV-AIDS Control program for Public Health, Seattle & King County. That compares with the 0.7 percent rate given on OraQuick's label.
The Seattle report is the third since June 16 that says testing with OraQuick gives more inaccurate results than the label claims. The U.S. Food and Drug Administration has asked OraSure to investigate the flawed readings with OraQuick, said Elliot Cowan, who oversees such tests for the agency.
``We're keeping an ear to the phone and making sure they're doing what they're supposed to do,'' said Cowan, chief of FDA's product review branch in Center for Biologics Evaluation and Research Office of Blood Research and Review, in a telephone interview. ``The ultimate goal is that the package insert appropriately represents the performance of the test.''
The U.S. Centers for Disease Control and Prevention has also been in touch with the Seattle officials. The Atlanta-based CDC recommends testing blood over oral fluid.
Still, the agency sent a ``Dear Colleague'' letter to doctors on Aug. 20, voicing support for oral fluid testing for HIV. The test has performed well ``overall,'' CDC said in the letter, and plays an important role in increasing the number of people tested for HIV.
``At this time, based on all the available data, we're not changing our recommendations regarding oral fluid rapid testing,'' said Richard Wolitski, acting director of CDC's Division of HIV/AIDS Prevention.
OraSure, based in Bethlehem, Pennsylvania, tracks the performance of its test and routinely investigates complaints, said Chief Science Officer Stephen Lee. The company keeps FDA informed of all the product information it gathers, he said.
``All the data that we've accumulated indicates the product continues to perform according to its FDA-approved claims,'' Lee said today in a telephone interview.
OraQuick, which takes about 20 minutes to process, detects human immune proteins called antibodies that betray the presence of HIV in blood and oral fluids. These antibodies generally appear in a person's bloodstream a few weeks after infection.
All medical tests provide some inaccurate positive and negative results, many with more frequency than OraQuick, FDA and CDC officials said. Rapid HIV tests must be confirmed with more accurate blood tests that take longer to process.
The Seattle public health department has sent its data to area doctors and clinics along with a warning to test blood rather than oral fluids whenever possible, said Seattle Public Health's Wood.
``Our recommendation is that people shouldn't use rapid oral tests if they can avoid it, but there are some situations where it can't be avoided and it's better than nothing,'' he said in a telephone interview.
Seattle began back-up testing of samples screened with OraQuick in 2003, Wood said. A laboratory test, called EIA, showed that the OraQuick missed 10 of 133 patients with antibodies to HIV in their blood.
Studies have shown that rapid tests aren't as sensitive as laboratory antibody tests, OraSure's Lee said. Other rapid tests have yielded similar results, he said.
Seattle also tested the samples with a more accurate test that looks for HIV's genetic material in the systems. This test can spot more HIV patients because the virus appears in patients' blood before antibodies. When compared with the RNA test, OraQuick missed 17 percent of infections, Wood said. The results may be published later in a journal, he said.
Saliva and Blood
Clinics depend on rapid oral testing to screen patients who prefer not to give blood and might not be reachable when results come back from laboratories days later. San Francisco's Magnet gay men's health center uses rapid oral testing with OraQuick routinely, and recommends that men at high risk also give a blood sample so the test's results can be confirmed, said director Steve Gibson.
New York City health clinics stopped using OraQuick to screen oral fluids in June, saying that the rate of inaccurate positive results ranged as high as 1.1 percent, or about five times higher than the 0.2 percent claimed on the package insert. The false positive results alarmed some patients who were mistakenly told that they might be infected, health officials said. The clinics still uses the test on blood.
Harvard University researchers said in August that nearly 3 percent of 849 people whose saliva was tested with OraQuick got false positive results. Rochelle Walensky, the Harvard associate professor who led the study, said then that while she would continue to use the test, AIDS testing experts should revise their expectations for OraQuick's accuracy.
OraSure fell 4 cents, or less than a percent, to $5.09 at 4 p.m. New York time in Nasdaq Stock Market composite trading.
Ireland-based Trinity Biotech Plc and Chembio Diagnostics Inc. of Medford, New York, also make rapid screens to detect signs of the AIDS virus in blood. OraQuick is the only one cleared to test both blood and oral fluid at a cost of about $12 per test, about $4 more than competitors, according to the CDC.
OraQuick generated $32.7 million in 2007 sales, or about 40 percent of company revenue, OraSure said in February.
To contact the reporter on this story: John Lauerman in Boston at firstname.lastname@example.org. Last Updated: September 3, 2008 16:11 EDT