(CBS) It started more than 30 years ago with the introduction of blood-sugar tests for diabetes and home pregnancy test kits.
Today, do-it-yourself medical testing is a multi-billion-dollar business.
Commercial kits now enable people to test themselves for signs of dozens of conditions and diseases, from allergies to prostate cancer.
But, as Early Show medical contributor Dr. Mallika Marshall explained Saturday, there's growing concern that all this may have gone too far.
The most familiar of these tests, the ones for pregnancy and diabetes - common over-the-counter products you can find in most pharmacies - are safe and effective, for the most part, Marshall says. These two types of tests have been under constant development for more than 30 years now, and they work. If you're a diabetic, it's important to keep tabs on your blood sugar, and for most people, that means monitoring it at home with such a kit. If you haven't been diagnosed yet and are curious whether you have diabetes or not, these tests are not for you. You need a special fasting blood sugar test, and perhaps other blood work to confirm the diagnosis with your physician.
The home pregnancy tests are pretty accurate, Marshall says, and to be honest, the urine tests used in doctor's office are pretty much the same thing. So if you think you might be pregnant and your period didn't come when you expected it to, go right ahead and use one of these tests in the privacy of your own home.
But, Marshall points out, there are lots of other kinds of tests. Some are available from retail pharmacies, but a far greater number and variety are available online.
At one local pharmacy, Marshall found tests for high blood pressure and cholesterol, drug tests - including for marijuana - and even HIV tests.
But, she pointed out, there are many others you can buy on specialized Web sites. On just one of them, Marshall found kits to test your blood alcohol level, tests for allergies and anemia, hepatitis, menopause, urinary tract infections, and many more. There are even tests that claim to assess your fertility and tell you the sex of your unborn child.
Just this month, a British watchdog group issued a leaflet suggesting that testing healthy people for hidden diseases isn't really such a good idea. While it may seem like a good idea to anticipate a medical problem and deal with it by using a home test looking for risk or early signs of disease, Marshall observes, in practice, testing healthy people can cause unnecessary alarm - or, worse, give false reassurance.
Critics of do-it-yourself testing say most medical screening tests aren't designed for healthy people, and that some tests can yield false positives for disease they are quite unlikely to get.
Marshall agrees, saying most of these health screening tests aren't really designed for use on healthy people, and so don't give an accurate forecast of disease someone may get in the future.
Originally, Marshall notes, most home medical tests were merely simplified versions of Food and Drug Administration-approved tests designed for professionals to use. Now, lots of these tests go straight to the home market. And that can be dangerous.
Marshall says doctors can't assure people about the safety or effectiveness of something they simply buy on the Web. Plus, no one knows we don't know if people are using the tests correctly.
Do you know how, Marshall asks, when you buy a cell phone or DVD player, you just figure you'll tinker with it until you get it to work, and you throw out the directions? Well, many people may treat these tests the same way, and fail to read the instructions or the fine print. At least if a medical professional is ordering the test, you know there are standards in place, and the professional will know how to interpret the results.
Marshall went on to say that there's concern the high cost of health care may prompt people to use home medical tests instead of going to a doctor for a diagnosis.
That, she says, sounds risky and, even though there's lots of frustration trying to get in to see your doctor, he or she has knowledge, intuition, and clinical experience. No home test can offer you that. So, if you're on the fence about using one of these tests, err on the side of caution and check in with your doctor first, Marshall urges.
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