December 12, 2005
CDC this week will issue a public health advisory recommending that all HIV-positive results from OraSure Technologies' oral, rapid HIV tests be followed up by the company's rapid "finger stick" test after reports of an "unusual" number of false-positive results from the oral tests in San Francisco and New York City, Bernard Branson, associate director of laboratory diagnostics at CDC, said, the San Francisco Chronicle reports (Russell, San Francisco Chronicle, 12/10). The oral test -- called the OraQuick Advance Rapid HIV 1/2 Antibody Test -- has been proven safe, effective and easy to use and currently is sold only to doctors and clinics. The test requires users to swab their gums and then place the swab in a holder. After 20 minutes, one line appears on the strip if the HIV result is negative, and two appear if the result is positive (Kaiser Daily HIV/AIDS Report, 11/4). The same OraQuick test also can test for HIV antibodies by using blood from a finger stick, a method that has not had comparable issues with false positives, according to the Chronicle (San Francisco Chronicle, 12/10). The San Francisco Department of Public Health announced that of 9,400 tests conducted at 14 public health clinics in the city in 2005, 49 HIV-positive results from OraQuick oral tests were later determined to be false positives (Vesely, Oakland Tribune, 12/10). Out of the total number of OraQuick oral tests that have been conducted in San Francisco this year, about 250 of the tests had HIV-positive results, according to Teri Dowling, manager of HIV counseling and testing for the city health department. New York City Assistant Health Commissioner Susan Blank said the city has recorded an average of about five false-positive results out of every 3,600 to 3,700 HIV tests conducted each month. Most of the tests were conducted with OraQuick oral tests and the false-positive rate was within the accuracy rate predicted by OraSure, Blank added. However, the city recorded 30 false-positive results in November (Grady, New York Times, 12/10). Deanne Sykes, a research scientist with the California Department of Health Services, said there also have been reports of false positives in Ohio (Malnic, Los Angeles Times, 12/10).
Branson said the CDC advisory likely will be issued in this week's Morbidity and Mortality Weekly Report. "What we intend to suggest is that if someone is tested with oral fluid and is positive, that person -- if it is possible at the clinic -- should get a finger stick test," Branson said. CDC likely will recommend that all results be confirmed by a traditional blood test, which can take about a week to process, the Chronicle reports (San Francisco Chronicle, 12/10). OraSure CEO Douglas Michels said that from Jan. 1 to Nov. 1 this year, doctors and clinics have reported 107 "confirmed complaints of false positives" from OraQuick oral tests out of 28,436 tests conducted for a specificity of 99.6%. "That is within the FDA's range (of acceptability)," Michels said, adding, "No product or diagnostic test is 100% sensitive or specific" (Howard Price, Washington Times, 12/10). Elliot Cowan, an FDA scientist who reviewed the oral test, said it was never meant to be an authoritative result but an indication that another test should be conducted. Cowan said 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" (New York Times, 12/10). An analysis of OraQuick results by San Francisco's health department completed last week -- which turned up 47 false-positive results -- led the California Department of Health Services to survey OraQuick results statewide, and although data from Los Angeles are pending, the department has not found problems with false positive results in other locales. Jeffrey Klausner, the San Francisco health department's director of sexually transmitted disease prevention and control services, said that he no longer uses the rapid tests at the City Clinic, the health department's primary location for HIV testing in San Francisco, but he added that the tests hold promise as a prevention tool and he is "not ready to discard" them citywide (Russell, San Francisco Chronicle, 12/9).
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, or sign up for email delivery at www.kaisernetwork.org/dailyreports/hiv. The Kaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service of the Kaiser Family Foundation, by The Advisory Board Company. © 2005 by The Advisory Board Company and Kaiser Family Foundation. All rights reserved.