When it's fine to test on your own, and when to leave it to the pros
Consumer Reports on Health: November 2008
The do-it-yourself movement is thriving at many local pharmacies. In addition to at-home pregnancy tests, you can buy kits to measure your cholesterol level and to diagnose urinary-tract infections and colon cancer. You can purchase devices to keep tabs on your blood pressure, blood-clotting time, and blood-glucose levels. And thanks to the Internet and walk-in labs, you can now order many of the same tests your doctor does.
In the best of circumstances, such home tests offer convenience, economy, and privacy—and they put the consumer in the driver's seat. Some can warn you of health dangers or offer reassurance that your vital signs are in order.
But not all home tests are accurate or easy to use. Even when they are, it often takes a medical professional's help to make sense of the results. "Home tests can help people become better partners in their health care," says Michele Curtis, M.D., associate professor of obstetrics and gynecology at the University of Texas Medical School in Houston. "But they should augment the health-care provider's role, not take its place."
The most useful home tests are those used to monitor chronic conditions that can vary from day to day or may be difficult to measure in the office. They can give you immediate feedback so you can make minor treatment adjustments, if necessary.
People with diabetes, for example, can modify their insulin dose as their blood-glucose levels fluctuate. Similarly, patients in one study who used anticlotting drugs such as warfarin (Coumadin and generic) were less likely to have major complications if they monitored their blood coagulation at home. And Curtis is encouraged when her patients with hypertension take home measurements, since that provides "valuable information about their blood pressure in the context of their everyday life," she says, not just at the doctor's office.
But it's smart to talk with your health-care provider before embarking on home monitoring. He or she can give you tips on when and how to take the tests and how to interpret the results. And not everyone with high blood pressure or diabetes needs home monitoring. For example, recent research suggests that people with diabetes who don't require multiple insulin injections and have reasonable control of the disease don't get much added benefit from frequent home testing. And for some, the needle pricks and tracking contribute to anxiety and depression.
If you decide to invest in a home blood pressure or blood-glucose monitor, keep in mind that the devices vary widely in price and accuracy. A ConsumerReportsHealth.org report found that automatic arm-type blood-pressure monitors tend to be more expensive but also more accurate than wrist monitors. But cost doesn't necessarily indicate quality. At only $20, the highest-rated blood-glucose meter, the OneTouch UltraMini, was also one of the least expensive.
While high cholesterol is also a chronic problem, cholesterol testing at home is rarely worthwhile. Cholesterol levels don't change much from day to day, and thus don't require frequent changes in drug dosages. Moreover, some home tests measure only total cholesterol, not the breakdown of LDL (bad) and HDL (good) cholesterol.
Getting your cholesterol levels monitored by your doctor is a better bet, as the test is likely to be simpler, neater, and less painful than those designed for home use—and more likely to be covered by insurance.
Tests to diagnose a condition rather than monitor it may be worthwhile when they are simple and accurate, don't require a lab for further analysis, and follow-up treatment based on the result is clear. For example, breath tests for blood alcohol levels are clear-cut: If the test is positive, someone else should drive.
Home-pregnancy tests also tend to be accurate. "In fact, it's the same test we use in the office," Curtis says. As long as the woman waits for a week after a missed period to do the test, the results are reliable. Of course, those who test positive should go to a health-care professional for the appropriate care.
The benefits of other home diagnostic tests are less certain. For example, women who suspect a vaginal yeast infection can safely test and treat themselves with over-the-counter drugs as long as they see a doctor if symptoms don't improve or recur. But if you're sure of the symptoms you don't need the test at all and can go straight to the treatment. And while home tests for urinary-tract infections may be accurate, the results are helpful only if your provider is willing to phone in a prescription for antibiotics without seeing you—something many doctors may be reluctant to do unless you have a history of recurrent infections.
Other tests can be hard to interpret, our medical consultants say. For example, it can be difficult for an untrained eye to discern the subtle color changes that indicate the possible presence of blood in the stool in some home colon-cancer tests. And in any case, that test isn't nearly as reliable at detecting malignancies as a colonoscopy. So a negative result on a home fecal-occult blood test, or, for that matter, in the doctor's office, can be falsely reassuring.
Lab work to go
You can order many of the same tests as your physician by going to a lab that accepts self-referred patients or by ordering a kit online and sending in a sample. In many cases they are the same or similar to doctors' versions and they are generally analyzed by qualified professionals. But cutting out the middleman—in this case, your health-care-provider—has drawbacks.
Even if you manage to decipher the results based on material provided by the lab or through your own research, a full interpretation often requires a medical history and physical exam. For example, one Web site touts its home test kit for C-reactive protein (a marker of inflammation) as a tool for early detection of heart disease. But the American Heart Association recommends the test only for people at moderate risk of heart disease, when an elevated level might tip the scales in favor of more aggressive treatment. And determining your coronary risk requires a thorough exam by your doctor.
Out-of-context testing can also lead to unnecessary anxiety, further tests, and unwarranted treatment. For example, the CA-125 test for ovarian cancer is a poor screening tool when used by itself. And the prostate-specific antigen test to detect prostate cancer can be abnormally high for several reasons, most of them not life-threatening.
But self-referred testing might be worthwhile when privacy is an issue, such as for people who live in states that do not guarantee anonymity for HIV test results. While our consultants still prefer face-to-face counseling for those undergoing HIV testing, the only FDA-approved home version, the Home Access HIV test, is as accurate as tests done in a doctor's office. Positive results are automatically retested, and you can phone in anonymously for results and medical and social-service referrals.
You could also consider direct-access testing if it will save you money or if you are in a particular rush to get the results. But even then, limit the tests to those recommended by your health-care provider, and make sure that the lab sends copies of the results to your doctor.
Questions to ask before you test at home
Will this test save you a trip to the doctor's office? If not, self-testing won't save you time or money.
Do you know the next step? Don't take a test if you don't know what you'll do with the information.
Is it FDA-approved? Approval suggests that a test is plausible, fairly accurate, and relatively easy to use.
What does your doctor think? Your doctor may have good reasons for discouraging you from doing home testing. And if you're reluctant to bring up certain issues with your doctor, it's time to look for a new one, not start testing at home.
Will it be covered by insurance? Many aren't, while those your doctor orders usually are.
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