Map of life expectancy at birth from Global Education Project.

Friday, February 10, 2006

An idea whose time may not have come

CDC estimates that about 25% of Americans who are HIV positive don't know it. It's very important that as many infected people as possible learn their status, so that they can obtain medical care which may slow the progression of the disease before they become symptomatic, and so that they can avoid infecting others. When a test for HIV first became available in 1985, legislation required that it be given only with informed consent. People who told their physicians that they engage in high risk behavior, or who presented for STD testing or with substance abuse problems or other indications of risk at clinics or social service agencies might be urged to consider testing, but it is illegal under most circumstances to test people without their knowledge and permission. Legislation in most states, and CDC guidelines for testing that it funded, required specific counseling protocols before people had blood drawn for the test, and when they were given their results.

The rationale for universal, elaborate pre-test counseling has weakened over the years, as the stigma and discrimination associated with HIV have lessened, but there continue to be good arguments for providing post-test counseling, particularly for people who test positive. Learning that one is HIV positive can be quite traumatic. Some people react with denial, and don't seek medical care or try to change their risk behaviors for weeks, months or years. People may have an addiction relapse, or exacerbation of their substance abusing behavior. They may become depressed. Post-test counseling aims at making sure people are connected immediately with services such as medical care, case management, emotional support, help deciding how and when to tell others, and the opportunity to cooperate with partner notification programs.

In order to increase the proportion of people who know their HIV status, testing is now recommended routinely for pregnant women, and efforts are being made to encourage screening of the general population through routine primary care. For people who test negative under these circumstances, there doesn't seem to be any particular reason to provide substantial counseling. There is still a good argument to be made for counseling individuals who sought out testing due to a known exposure risk, so that they don't take the negative test as a license to continue unsafe behavior.

Last year, the OraQuick HIV test, manufactured by OraSure Technologies, went into widespread use. It's an important advance because it produces a result within 20 minutes, unlike previous tests that required people to come back on a later date to get their test results. Unfortunately, about 30% of people do not return. Rapid testing is not quite as specific as the laboratory tests, so a positive result is reported to people as an indication that they may be infected and still need a confirmatory lab test. Nevertheless, they are still there to be counseled and measures can be taken to greatly increase the likelihood that they will remain in contact with the test site to get their confirmatory results and be connected with appropriate services.

Since 1996, home test kits have been available, but they require the user to send a blood sample to a laboratory and receive the results by telephone. While anonymous telephone counseling is certainly inferior to face-to-face counseling in settings where backup services are immediately available, FDA approval was enough for the kits to be marketed, even in states that objected. While some people are sanguine about this, on the basis that there hasn't been any reported increase in the rate of suicide associated with home testing, I would say that we really don't have any information about how people respond to getting positive results over the phone and whether this is really such a great idea.

But now OraSure wants to market a rapid test over the counter, which would enable people to read their own test results at home without having to talk about it with anyone. Alexi Wright and Ingrid Katz, writing in the New England Journal of Medicine (Feb. 2 -- subscription only) seem to think this is just a terrific idea, as did 18 out of 20 people who spoke at an FDA panel to consider the application. I am not convinced. We need evidence to show that this is not going to be harmful to people.

In addition to the emotional and behavioral risks I have mentioned, the OraQuick test has been associated with clusters of high rates of false positives. If the problem of false positives is resolved, there now seems a good chance the FDA will approve the rapid test for home use. I'm afraid we'll learn about the negative consequences after the test goes to market, as we have with so many drugs. If this is going to happen, it should be done on a small-scale, experimental basis in limited markets, so that we can make a decision based on evidence, not commercial interest.

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