Occult HIV Infections Unmasked by Rapid Tests

ATLANTA, June 22 -- Rapid HIV testing with on-the-spot results during emergency room visits or at community events appears to be a feasible way to identify people who are infected with the virus and don't know it.

So it would seem on the basis of a pair of studies published in the June 22 issue of Morbidity and Mortality Weekly Report. One covered free rapid testing in emergency rooms, and the other involved gay pride events at such sites as tents, mobile testing units, community centers, churches, and bars.

Yearlong pilot programs in three urban emergency departments found that more than half of the patients offered a rapid HIV agreed to be tested, according to Edward Telzak, M.D., of the Bronx Lebanon Hospital Center in New York, and colleagues.

And of those who were actually tested, Dr. Telzak and colleagues found, 1% proved to be HIV-positive and nearly 90% of those were linked to HIV care and treatment.

The three pilot projects -- in New York, Los Angeles, and Oakland -- were intended to see how acceptable offering such testing would be to patients arriving for emergency treatment.

The reports come as the CDC is recommending a so-called opt-out approach to HIV testing, in which it would become a routine part of medical care, without the need for separate consent and pre-test counseling.

The pilot projects, however, followed the standard form, in which patients were given pre-test information, specific written consent was required, and HIV counselors were present to provide more information in the event the test was positive.

Signs and brochures advertised the free tests, which used the OraQuick Advance test, and patients were offered the test if they said they were HIV-negative or did not know their status.

Patients whose rapid test was positive were given risk-reduction counseling and asked to give a second specimen for confirmatory testing by Western blot.

An HIV test was offered to 34,627 (18.6%) of the 186,415 people who sought care, although the proportions varied from 2.1% in New York to at 47.7% in Oakland.

Overall, 19,556 (56.5%) of those offered testing agreed to be tested and 9,365 actually got the tests, but the proportion of those were tested varied by site -- 99.8% in Los Angeles, 99.4% in New York, and 38.5% in Oakland.

The testing identified 97 people with newly diagnosed HIV infection, of whom 85 (or 88%) then had at least one follow-up visit for HIV treatment, the researchers found.

In an accompanying editorial comment, the CDC said the test program -- although not in the same format as proposed by the agency -- shows that routine testing "is a feasible strategy for identifying persons with previously undiagnosed HIV infection."

In a companion article, researchers from several states and cities reported on using rapid HIV testing during 11 gay pride events in nine U.S. cities during 2004 through 2006.

The testing took place in "diverse settings, including tents, mobile testing units, community centers, churches, bars, and hotel rooms," the researchers said.

During the events, 627 men older than 18 took part in a behavioral assessment and 543 reported that they were HIV-negative or did not know their HIV status.

Of those, 133 were given a rapid HIV test (also using the OraQuick system) and eight (or 6%) tested positive. Two of those could not be located for later follow-up.

The report suggests that such events can be "an important strategy" to reach gay men who might not otherwise get tested, the CDC said in an accompanying editorial comment.

But the agency noted that in several cases, the demand for the testing outstripped available resources, which limited the effectiveness of the program.

As well, follow-up was difficult, since 25% of those who tested positive could not be located later for confirmatory testing and possible HIV care, the agency said.