PEP rally! Rapid tests coming out for HIV

Easing ICP decisions following needlesticks

New rapid HIV tests are becoming available to hospitals as investigational devices, meaning recent problems determining the need for post-exposure prophylaxis (PEP) of health care workers may be coming to an end, Hospital Infection Control has learned.

The problems began in October 2000, when the only licensed rapid HIV test in the United States — the SUDS (single-use diagnostic system) distributed by Abbott Laboratories in Abbott Park, IL — temporarily dropped out of the market due to manufacturing problems.

Many ICPs had come to rely on the rapid tests to guide decisions on PEP by quickly testing the source patient following a needlestick. With patient serostatus rapidly available, health care workers would not needlessly be put on powerful PEP drugs to prevent HIV infection. (See Hospital Infection Control, November 1999, under archives at www.HIConline.com.)

"We finally talk the doctors into using it, they finally agree to it, and we get everything going — and then you don’t have it," says Pam Wood, RN, CIC, COHNS, an ICP at Parrish Medical Center in Titusville, FL. "Now what do we do?"

Some relief is coming from Ireland, where Dublin-based Trinity Biotech makes the Uni-Gold HIV test. Trinity has been granted approval from the Food and Drug Administration (FDA) to begin a limited trial with the product under an investigational device exemption (IDE). While distribution may expand as the program progresses, the initial deal allows Trinity to provide HIV tests for 20 hospitals that apply to participate in the project. The clinical trial sites will be recruited through Trinity Biotech’s web site at www.trinitybiotech.com.

"The protocol is now on the web site," says Síle MacMahon, Trinity product manager for HIV rapid tests in Dublin. "So they can go and see exactly what we are able to do under the IDE, and if they have any queries, there is direct e-mail."

The costs during the trial phase will be around $60 a test kit, which can provide results in less than 15 minutes, she says. Under the FDA approval, the test is limited for use to two situations:

1. needlestick injuries;

2. pregnant women at high risk of HIV who present for delivery.

In those circumstances, the ability to diagnose HIV status rapidly was considered crucial. Clinical data gathered during the trials will be submitted to the FDA. The product has been used extensively outside the United States, particularly in high-prevalence HIV areas such as sub-Saharan Africa and India.

CDC brokering deal with FDA

In addition, two other rapid HIV tests are expected to be available soon on the U.S. market under a deal being worked out between the FDA and the Centers for Disease Control and Prevention. The CDC is lobbying for similar IDE approval for use of two rapid HIV tests in conjunction: the Determine (Abbott Laboratories) and the Oraquick (Epitope Inc., Beaverton, OR), says Bernard Branson, MD, medical epidemiologist in the CDC division of HIV/AIDS prevention. "We are planning to scale up to meet the need [nationally]."

The two tests are currently not approved by the FDA for use in the United States, but the CDC program could provide a step in that direction
as the two-step IDE protocol is geared up in the coming months. "We have been doing an ongoing evaluation of different rapid tests," he says. "We think that it probably makes sense to come out using two tests together so you can eliminate or at least substantially reduce the false-positive problem."

Plans call for using both rapid tests on a needlestick source patient, but Branson concedes there is about a one in 500 chance that the two assays will show different results. "In general, with the tests that we are using, we have had more trouble with false positives than with false negatives, but we don’t have enough information yet to say this is exactly what you do [in that situation]," he says. "It’s pretty rare. They agree most of the time."

Seeking a reliable pattern

Similarly, the false-positive/false-negative pattern of the Uni-Gold test will be followed as part of evaluations in this country, he says. "That test can certainly help, but we don’t know how well it will perform," Branson says. "The situation with SUDS was that the performance characteristics were reliably established. If that test was negative, you did not have to worry. If the test was positive, it might be false positive, but still the vast majority of tests came out [reliably] negative so the probabilities were with you."

Amid the flurry of activity, there is also the expected return of the SUDS test to the market, meaning that as many as four rapid tests could be available in the United States.

"We have a lot of customers hoping we get [SUDS] back as soon as possible," says Don Braakman, Abbott spokesman. "We’re doing everything we can to get this product back on the market, but I just can’t give you a timeline at this point."

Regardless, the availability of the new tests should ease woes for ICPs, some of whom have had to resort to having a lab technician on call to run a single enzyme-linked immunosorbent assay test (as opposed to batching) after a needlestick. "It has definitely put people in a bind because everyone had geared up for using it, especially for post-exposure prophylaxis," Branson says. "Having rapid results clearly makes you a better decision maker."