A little bit of the doctor's office is now available in the privacy of your own home. At-home tests for pregnancy and blood sugar have been around for years, but they're being joined on the shelves by tests that answer a host of medical questions, from whether your teen is using drugs to whether you have HIV.

Check to make sure tests are approved by the Food and Drug Administration. Unapproved tests are more likely to deliver false positive or false negative results. Share the results with your doctor soon after you get them. That way he or she can check to make sure that the results are accurate and decide what action, if any, to take. Follow the directions carefully.