External quality assessment

External quality assessment (ex q a) is the challenge of the effectiveness of a laboratories quality management system. EQA typically refers specifically to the challenge of quality systems in a medical laboratory. The term external refers to the fact that an organizer outside of the laboratories organisation provides a statement of quality to the laboratory. External quality assessment (ex q a) is the challenge of the effectiveness of a laboratories quality management system. EQA typically refers specifically to the challenge of quality systems in a medical laboratory. The term external refers to the fact that an organizer outside of the laboratories organisation provides a statement of quality to the laboratory. Typically, an EQA scheme consists of several rounds per year. In each round several (or many) participants receive test items, which are also called samples. The EQA organizer is also called the provider. The organizer ensures that the test items are sufficiently similar and homogeneous, typically according to ISO 13528. Often the test items' properties and analyte concentrations are known to the organizer, but not disclosed to participants before the final report. However, there are also many schemes where the organizer doesn't know the sample composition. The participants' results are then compared to check if any participant had a bias towards e.g. higher values, or an unexpected imprecision. At the end of each round, the EQA organizer sends out reports and/or certificates to the participating laboratories. Laboratories are often accredited for ISO 17025 and ISO 15189 compliance. Internationally, the International Laboratory Accreditation Cooperation establishes global recognition of these standards. Locally, conformance with ISO standards is checked by accreditation bodies. These often mandate, but always encourage laboratories to participate in EQA schemes.