CLIA regulations create a "level playing field" in which all laboratories must meet appropriate criteria in competing with each other. But the quality of services still varies among laboratories. To ensure that you are receiving the best quality services, there are steps you can take to check for yourself.

• Your first consideration is the kind of laboratory that will be testing your specimen. Most physician office laboratories run only simple tests and thus are exempt from the more stringent standards applied to the "complex" testing laboratories. There are no education or training requirements for the personnel in these labs, so ask your doctor about the qualifications of those staffing the lab. Also ask if the lab participates in any outside education or quality checking programs.

• The major requirement for physicians' offices that perform only simple tests is that they follow the manufacturer's instructions for the tests, but a recent U.S. Health and Human Services Department study found that nearly one-half failed to do so. Can the person who will perform your test explain to you the specified procedures? Is the lab following proper specimen labeling and handling procedures - for example, was your specimen labeled with your name in your presence?

• If your tests will be run by a larger, more complex laboratory, the lab will undoubtedly fall under the CLIA accreditation requirements, but you still might like reassurance about its quality. Ask your doctor about what considerations went into his or her choice of the laboratory. What criteria did your doctor use? How long has your doctor been dealing with this laboratory? How does your doctor verify the accuracy of the test results?

• The sample collection process itself should provide you some clues: was the specimen properly labeled? Were you given clear and adequate instructions if you collected the sample yourself?

• Is your doctor aware of the laboratory's accreditation status? Because labs are so closely regulated, if you'd like reassurance on the laboratory's accreditation and certification, you can check this yourself by visiting various websites. The U.S. Centers for Medicare and Medicaid Services posts a list of accredited laboratories as well as those that have had some trouble. Through the links listed in the Sources for this article, you can find other inspection and certification agencies that might have further information on the lab you're interested in.