An Overview of Allowable Total Error in the Clinical Laboratory

Allowable total error (ATE) is a quality concept that defines acceptable analytical performance for a clinical laboratory assay. ATE will vary in terms of the amount of error permissible not only between assays but also based on the test setting and the assay's clinical use. In the clinical laboratory, ATE limits are routinely applied, for example, when evaluating new analytical methodology or equipment for patient testing, troubleshooting unacceptable quality control, or in evaluating instrument comparability.

Currently, there are no universally applicable standards for defining the maximum magnitude of allowable error. However, there are several resources available for users to consider when setting ATE limits. Examples include clinical outcomes studies, biological variation of the measurand, state-of-the-art, professional organizations, and requirements set by regulatory agencies and proficiency testing/external quality assessment scheme organizers. Each of these approaches varies in terms of the resulting magnitude of allowable error for the same assay. This review describes these resources in more detail and discusses the strengths and weaknesses of each approach.

ATE users should be aware of different resources and their limitations before defining acceptance criteria for an assay in their clinical laboratory.