FDA Approves HIV Home-Use Test Kit 186
Hugh Pickens writes "The LA Times reports that the Food and Drug Administration has approved the first over-the-counter HIV test kit, allowing people to test themselves in private at home and get preliminary results in less than 30 minutes. The test, which works by detecting antibodies in a swab from the gums, should not be considered final — in trials, the test failed to detect HIV in 1 in every 12 patients known to be infected, and returned false positives in 1 in 5,000 cases. The new at-home test, called OraQuick, will be sold in supermarkets and pharmacies and manufacturer, OraSure, has not said how much the test will cost, only that it will be more than the $18 cost for the professional kit. The federal Centers for Disease Control and Prevention estimates that of the 1.2 million people in the U.S. with HIV, 1 in 5 is not aware of the infection and that a disproportionate number of the 50,000 new cases of HIV each year is linked to people who have not been tested. Chip Lewis, a spokesman for Whitman-Walker Health, which provides AIDS care in Washington, says at-home testing could reach some people who didn't want to go to a clinic but removing medical professionals from the process could cause problems. 'It's not like a home pregnancy test,' says Lewis. 'You need really a lot of information about how to read the test, how to use the test properly.'" Back in May, we reported that a panel of FDA experts recommended approval of an over-the-counter HIV test.
Use it on someone else? (Score:5, Interesting)
Nobody seems to have noticed the "best" thing about this test: it should be possible to use it on your partner. With or without their consent. So you can invite that random girl at the bar home for a drink and a swab, or secretly swab your boyfriend while he's sleeping, just in case he's lying to you about being clean.
Unethical? Yes. Unromantic? Yes. False sense of security? Yup. But potentially lifesaving? Also yes.
Re:It's only 92% accurate ... (Score:5, Interesting)
They should sell these (Score:3, Interesting)
in night club/bar bathrooms.
It's 1:40 and you've hooked up with your last resort, you go back to your place but before you put yourselves at risk, take 5 minutes and show each other that you don't have HIV.
I say this is all around win!
LK
Sensitivity is only part of the story (Score:4, Interesting)
To review, sensitivity is the probability of a positive result given that the tested individual is actually positive; specificity is the probability of a negative result given that the tested individual is actually negative. The OraQuick swab test has a rather low sensitivity, meaning that there is a roughly 1 in 12 chance that an HIV-positive individual incorrectly tests negative (type II error). But it has a relatively good specificity, meaning that there is a roughly 1 in 5000 chance that an HIV-negative individual incorrectly tests positive (type I error).
The value in granting FDA approval for OTC sales of OraQuick, then, is to address the need for the vast majority of the population, which is HIV-negative, to feel reassured that they are in fact negative. Historically, one of the biggest challenges in HIV education has been overcoming the fear and stigma of testing. Making testing available OTC greatly improves the likelihood of getting regularly tested.
But what of those pesky type II errors? Yes, given that an individual is actually HIV-positive, the chance that the test fails to detect is is 1 in 12. But that is NOT the same thing as saying that given a negative test result, the chance the person is actually HIV-positive is 1 in 12. For the general population, that probability is much smaller. In fact, I leave it as an exercise for the reader to calculate the negative predictive value (which would require the prevalence of HIV in the US population). Now, if we were talking about using OraQuick on a very high-risk group, we would expect many more false negatives, so a more appropriate test would be the standard ELISA blood test, followed by a confirmatory Western Blot. But remember, FDA approval of OTC OraQuick is targeted at the general population. If you know you're in a high-risk group, you presumably would be getting regularly tested at a public health clinic, and OraQuick isn't necessarily your best choice. But it's still better than not getting tested at all.
Finally, remember that any reasonable person who tests positive with OraQuick would want a follow-up test to be sure. (Someone who tests negative, however, is much more unlikely to want a follow-up test.) So we don't really need to worry about type I errors, except for the panic and anxiety such a rare outcome might cause.