This is only a test: Taking medical exams at home

The do-it-yourself movement is thriving at many local pharmacies, according to the editors of Consumer Reports On Health. In addition to at-home pregnancy tests, people can buy kits to measure their cholesterol level and to diagnose urinary-tract infections and colon cancer. They can purchase devices to keep tabs on their blood pressure, blood-clotting time and blood-glucose levels.
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 people of health dangers or offer reassurance that their vital signs are in order.
But the editors of Consumer Reports On Health warn that 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.
Tracking tools
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 provide immediate feedback so minor treatment adjustments can be made, 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 anti-clotting drugs such as warfarin (Coumadin and generic) were less likely to have major complications if they monitored their blood coagulation at home.
But it’s smart to talk with a healthcare provider before embarking on home monitoring. He or she can offer tips on when and how to take the tests and how to interpret the results.
Do-it-yourself diagnosis
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. As long as the woman waits for a week after a missed period to do the test, the results are reliable.
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 you can go straight to the treatment.
Other tests can be hard to interpret, Consumer Reports On Health’s 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.
Lab work to go
It’s possible to order many of the same tests as a physician by going to a lab that accepts self-referred patients or by ordering a kit online and sending in a sample. But even if someone manages to decipher the results based on material provided by the lab or through their 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.
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.