As defined by the Clinical Laboratory Improvement Amendments of 1988 (CLIA), waived tests are categorized as “simple laboratory examinations and procedures that have an insignificant risk of an erroneous result”. The Food and Drug Administration (FDA) determines the criteria for tests being simple with a low risk of error and approves manufacturer’s applications for test system waiver.

Tests waived by CLIA also:

• Pose no reasonable risk of harm to the patient if the test is performed incorrectly
• Are cleared by the FDA for home use
• Are considered non-technical requiring little or no difficulty

If a lab is conducting only waived testing, it must have a valid Certificate of Waiver (COW) from CLIA and the lab will not be routinely inspected for laboratory compliance. However, COW labs may be randomly inspected as part of a compliance investigation to ensure that they are only performing waived testing.

Although CLIA waived tests must be simple and have a low risk for erroneous results, this does not mean waived tests are completely error-proof. Errors can occur anywhere in the testing process, particularly when the manufacturer’s instructions are not followed and when testing personnel are not familiar with all aspects of the test system.

Some waived tests have potential for serious health impacts if performed incorrectly. For example, results from waived tests can be used to adjust medication dosages, such as prothrombin time testing in patients undergoing anticoagulant therapy and glucose monitoring in diabetics. In addition, erroneous results from diagnostic tests, such as those for human immunodeficiency virus (HIV) antibody, can have unintended consequences. To decrease the risk of erroneous results, the test needs to be performed correctly, by trained personnel and in an environment where good laboratory practices are followed.

Many waived tests are not done according to designed protocols, with more than 50% of such tests reportedly done incorrectly, and result in medical errors, some with fatal consequences.

The lengthy list of CLIA waived tests can be found here.