February 5, 2001
Approximately one third of HIV-positive patients in this country do not know they are infected. This has obvious public health implications, because these subjects continue to transmit HIV, and also the delay in access to care is probably associated with a worse clinical outcome for these individuals.
How can we capture this population?
It has been suggested that HIV testing should be offered whenever a group of individuals at risk has access to medical care. Using rapid testing that provides same-day results has been considered a possible strategy to improve the identification of HIV-positive individuals, and to allow the pre- and post-test counseling that we are required to do by law to be conducted in a short period of time.
In this study, from Emory University and Grady Hospital in Atlanta, Dr. Franco-Paredes et al. tested the utility of two different HIV tests used in the setting of a busy urban clinic. They compared the standard HIV test and a rapid HIV test made by Abbott, which in theory takes around 15 minutes to get the results.
They offered one test or the other every other month during a period of six months. There were more than 13,000 eligible visits in this clinic during that period of time and the test was offered approximately to half of those subjects. It was not clear in the poster what were the criteria to offer the test or not.
Approximately 40% of those subjects accepted to have the test done, and 70% of those tests were finally performed. They identified 69 cases of HIV infection in patients obviously unaware that they were HIV positive. However, there were delays in communicating the results to the patients even with the rapid test, and only 25% of the patients really got the results of the test that was done. That figure increased to 77% of those that tested HIV positive (simply because they made a big effort in trying to reach those patients). What was really sobering was that only around one third of the newly identified HIV-positive patients did finally make it to medical care and even fewer got antiretroviral medications.
A study like this clearly shows the problems implementing the logistics of an approach like rapid testing in a community setting. These ideas always look better when you think about them than when you have to deal with the details. The long-term delay between performing the test and the subject getting the results was not a problem of the test itself, which can be done in only 15 minutes, rather the flow of the patients in the clinic was the problem. The tests had to be "batched," so many patients had to wait several hours and thus many left the clinic without finding out their results. If you have ever been in an emergency room in a big city hospital you know what they are talking about.
The authors of the poster thought a test that can be performed in the room at the same time that the patient is being evaluated -- so pre-test and post-test counseling can be done "in-situ" -- would perform better (and he is probably right). This specific test, which is the only rapid test approved by the FDA, as far as I know would perform better in a less-busy setting, or in a clinic with a better overall flow.
There have been several posters presented about rapid tests for the diagnosis of HIV in this Conference. One of them is a saliva-based test. Maybe that test would do better in a setting like the one contemplated in this study.
For the future it is critical, if we want to prevent further transmission of HIV, that we identify all HIV-infected individuals, so we can educate them in how to prevent transmission to others, and provide them with access to care. Rapid testing will be part of that strategy, even if this study showed that it did not work well in a busy inner-city clinic.
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