The agony after the injury: Are rapid HIV tests an answer for exposed workers?

ICPs using test to streamline PEP, end turmoil

Adding emotional insult to occupational injury, too many health care workers are suffering days of psychological turmoil and fear of infection after needlesticks because rapid HIV tests that could quickly determine the serostatus of the source patient are likely underused in America’s hospitals, clinicians tell Hospital Infection Control. Moreover, infection control professionals who have added the rapid HIV test to their postexposure protocols report a striking response from angst-ridden health care workers in the traumatic aftermath of a potentially deadly needlestick.

"You can even get doctors who will have an exposure and come in and break down on you, [saying], I never thought this would happen to me,’" says Pam Wood, RN, CIC, COHNS, an ICP at Parrish Medical Center in Titusville, FL. "When you tell them if I can get the [patient’s] blood I can have the results back in an hour, they say, you’re kidding.’ They know whether or not they are going to sleep that night."

Such timely knowledge of one’s fate has more pedestrian benefits as well, allowing hospitals to avert losses in productivity of clinical staff. "I just had an exposure this morning and it took about an hour and five minutes [to get results]," says Linda Jacquemin, RN, BSN, team leader of the employee health department at Mercy Hospital Partners in Cincinnati. "You just can’t imagine how the employees are relieved. It doesn’t consume their life for two or three days. They are able to continue working and put this matter to rest, knowing that we will do subsequent testing on hepatitis B and C. They are able to continue their job."

Moreover, health care workers suffering needlesticks are increasingly being administered powerful HIV postexposure prophylaxis (PEP) drugs that have been recommended by the Centers for Disease Control and Prevention to stave off seroconversion.¹ If the exposure warrants, PEP usually is administered as quickly as possible to ensure efficacy until the source patient’s HIV status can be determined.

While situations vary according to individual hospital resources and laboratory testing "batching" arrangements, the results of conventional patient testing may not be available for days or even weeks under some protocols described to Hospital Infection Control. That means workers who have actually been exposed to an HIV-negative patient may spend days wracked with nausea and other common side effects of PEP drugs. (See related story, p. 143.)

"Health care workers oftentimes have been put blindly on automatic three-drug PEP, only to find a week later that a source patient tested negative," says Robert Ball, MD, MPH, infectious disease consultant epidemiologist at the South Carolina Department of Health in Columbia. "[Health care workers] often harbor great resentment against a system that shoots first and asks questions later, especially since a third to a half of those taking HIV PEP often have dreadful side affects. Although they are not fatal, they are unnecessary and result in anxiety and resentment, lost time from work, lost productivity — often in situations where an [inexpensive] test could have answered the question."

While at least four other rapid HIV tests are in the research stage, only one such test has been approved by the Food and Drug Administration. The SUDS (single use diagnostic system) test lists for $10.71, but pricing may vary by volume purchased, according to the product distributor, Abbott Laboratories in Abbott Park, IL.

The test must be run in a clinical lab rather than at bedside, but results are generally available in an hour, ICPs tell HIC. Industry sources say the test is currently being purchased by some 1,400 hospitals and clinics nationally, underscoring to proponents like Ball that more facilities should consider it an option for beleaguered health care workers.

"This test is significantly underutilized throughout the country, and that is a real understatement. It’s amazing, some people have never even heard of it," says Ball, who has no proprietary ties to the product but is urging greater use of the test nationally due to its clinical benefits. "The beauty of it is that within an hour, we can tell the health care worker if she does or does not have to take four weeks of medicine and suffer 12 months of follow-up testing anxiety," he says.

Of course, as with any antibody test, if the source patient has been recently infected and is in the so-called window period (approximately 25 days) prior to developing antibodies, the test will return a negative result. The CDC guidelines note that if the source patient is HIV-seronegative and "has no clinical evidence of AIDS or symptoms of HIV infection," then no further testing of the source is needed.

"If on the other hand, someone is still anxious about the window period, then retest the source patient one to two months later, or retest the source patient using a qualitative PCR [polymerase chain reaction]," Ball says. "Source patients get harder and harder to find the longer away from the exposure incident you are. But within the first month or so, you can often find them. Or again, you can use a qualitative PCR on the [patient’s] blood."

Though individual ICPs and hospital policies may vary on whether to use the rapid tests in deciding whether or not to implement HIV PEP protocols, Wood says she is consistently getting rapid test results within an hour. She then makes the decision on prophylaxis. "If the results come back negative, you don’t have to put them on drugs," she says. "The best-case scenario with send-out [testing] is three days. Worst-case scenario is six weeks. That was the longest it took when we had to wait on western blot [testing]."

Indeed, rapid tests can be particularly useful at hospitals that have limited in-house laboratory capabilities, which generally translates to longer waiting periods for test results, says Wood, who works at a 160-bed hospital. "For the big medical centers that run their own HIV [tests] and can do them [frequently] and have the results back, it is not going to make that much difference," she says. "It’s for us little guys that have to send everything out and have to wait on the results. Plus the fact that you have an employee who is bouncing off the walls anyway. They don’t sleep, and the medicines make them deathly sick because of all the side effects. If you can tell them within an hour that the test is negative, to me, it’s a no-brainer."

The current CDC guidelines for PEP recommend performing HIV antibody testing of an exposure source as soon as possible. Hospitals, clinics and other sites that manage health care worker exposures should consult their laboratories regarding the most appropriate tests to use to expedite the results, the CDC recommends, adding that "an FDA-approved rapid HIV antibody test kit should be considered for use in this situation, particularly if testing by EIA (enzyme immunoassay) cannot be completed within 24 or 48 hours." Advocates like Ball have been urging CDC officials to underscore that recommendation, but an agency epidemiologist says more data would be needed to more strongly recommend the test.

"I think we’d need to have more information on need and how quickly results are available," says Linda Chiarello, MS, epidemiologist in the CDC hospital infections program. "If systems are in place currently to get a fairly quick turnaround on the [EIA] test, it may not be necessary."

And even though the rapid test itself can be run quickly, there still can be delays through such peripheral issues as obtaining the patient’s blood sample and ensuring someone is staffing the lab to perform the test. State laws may vary on the patient consent needed in such cases. Under Florida law, for example, Wood says she can run the test if need warrants and she already has a sample of the patient’s blood. "If I have [the source-patient] blood on hand, and they refuse to sign the consent, and I have a need to know — which I do — I can run the test without consent," she says. "But I always try to get consent, and I have only had one person in the eight to 10 years I’ve been [in infection control] turn me down."

If there are delays, it is probably best to administer an initial PEP regimen after a significant exposure rather than wait for test results, Chiarello says, noting that the greatest utility for the rapid test may be in the area of continuing or discontinuing the protocol.

"If it’s a positive [result], you start the prophylaxis, and it has to be confirmed [by other tests] anyway," she says. "But at least a negative test prevents the health care worker from unnecessarily being exposed to antiretroviral drugs, and that’s an advantage to the worker. It is also going to ease their mind to a great extent. It really depends on what resources are available within an organization to have HIV testing performed and how quickly they can get the turnaround on the test results. One of our big concerns is health care workers who have to wait a week a two to get a test result and are unnecessarily put on antiretroviral drugs — with all of their side effects — for that length of time."

The CDC also is concerned about false positives associated with the test, particularly in areas with low HIV prevalence in the patient population, adds Bernard Branson, MD, medical epidemiologist in the CDC division of HIV/AIDS prevention. (See chart, at right.) "When you use any single screening test in a potentially low-prevalence population — and for a lot of your needlestick exposures, they may be low-prevalence source patients — you are going to have a number of false positives," he says. "That is not necessarily because the test is bad; it is a direct function of the prevalence."

A possible solution to the problem may come out of an ongoing study in Los Angeles, where the CDC is working with both the currently available test and several other rapid tests that are in premarket research stages, he says. "We can potentially [develop] an algorithm consisting of more than one rapid test," he says. "So if you do one and it’s positive, you have another one you can do right away in order to help corroborate the results. [We are looking] at their predictive value when used in combination."

While a few false positives may occur, the rapid test’s prime utility is that there have been no documented false negatives, Ball adds. "A lot of folks don’t understand the false positives, and assume there is something wrong with the test," Ball says. "The whole purpose of having a rapid screening test that is supersensitive is to get the true positives, with even a few false positives in the same ballpark. Keep in mind that most SUDS tests are going to be negative, and those are going to be true negatives." Regardless, Ball recommends using confirmatory testing to verify the rapid test results in any case.

Still, Jacquemin says the rare false-positive HIV test is unsettling to health care workers, even after they have been counseled that it may occur. "We do that at the time that we give them the results, but they usually don’t hear that. All they hear is positive,’" she says. With the vast majority of rapid test results being true negatives, however, the false-positive issue does not undermine the test’s value to her program, she notes. "Our hospital batches HIV testing, and they usually do it on Monday, Wednesday, and Friday, so it just depends on when the exposure happened," she says. "Our worse-case scenario was if an exposure happened on Friday morning and it was a Monday holiday, then the test wouldn’t be run until Wednesday. So that’s five days of worry we feel we can take away by having the rapid [test]."

In addition, using the rapid test as part of an overall protocol that includes a 24-hour "hotline" for exposure reporting has resulted in some $100,000 saved annually in unnecessary emergency room visits by exposed workers, she adds. "We used to send every exposure down there for an evaluation. But now only the ones that are unknown sources or the source is rapid-HIV-positive go to the emergency room," she says. "We can handle most exposures right over the phone, and they don’t leave their department and spend three hours in the ER waiting room."

Reference

1. Centers for Disease Control and Prevention. Public Health Service. Guidelines for the management of health-care worker exposures to HIV and recommendations for postexposure prophylaxis. MMWR 1998; 47(No. RR-7):1-33.