While many lab errors are out of your control, there are steps you can take to increase the chances of accurate results.
Ask your doctor about the lab she uses. It should be accredited and approved by the College of American Pathologists (a sign that it meets high standards).
If you can see the test tube or slide, double-check that your name is on it; if you're in the hospital, make sure your wristband is accurate.
If the result of the test is a surprise, ask your doctor: "Did you expect this? Do you think this is what I have?" If the answers are no, consider repeating the test.
Get a copy of all lab results and reports, suggests Susan Sheridan, president of Consumers Advancing Patient Safety. "Patients may not realize they have the right to these," she says.
Have a specialist read your slides. With a skin sample, for instance, you'll improve odds of the right diagnosis if it's viewed by a dermatopathologist, says Mark Lebwohl, M.D., chairman of dermatology at the Mount Sinai School of Medicine in New York City. Your insurer may not cover a specialist, so you'll have to decide whether to pay for it yourself.
Testing Your Test: How to Get a Second Opinion
For certain diseases, false positives or false negatives are common, and some labs routinely have two pathologists read these more challenging slides. Labs may also elect to repeat tests before reporting certain diagnoses, such as HIV or cancer. But you also have the right to have your slides reviewed by another pathologist or another hospital, and for a serious diagnosis, that's smart. Ask your doctor where he suggests you send them. The office should be able to get the sample transferred (you'll probably have to sign a release and pay for records to be copied). If your doctor questions your request, you can call a lab yourself. "Specimens are part of your medical record and you have the right to them," says Stephen Raab, M.D., of the University of Pittsburgh Medical Center. Most insurers will pay for a second opinion.