{"id":5337,"date":"2020-08-26T09:43:54","date_gmt":"2020-08-26T09:43:54","guid":{"rendered":"https:\/\/clinlabint.3wstaging.nl\/external-quality-assessment-eqa-for-trace-element-measurements-in-clinical-laboratories\/"},"modified":"2021-01-08T11:36:47","modified_gmt":"2021-01-08T11:36:47","slug":"external-quality-assessment-eqa-for-trace-element-measurements-in-clinical-laboratories","status":"publish","type":"post","link":"https:\/\/clinlabint.com\/external-quality-assessment-eqa-for-trace-element-measurements-in-clinical-laboratories\/","title":{"rendered":"External Quality Assessment (EQA) for trace element measurements in clinical laboratories"},"content":{"rendered":"

External Quality Assessment (EQA) is the cornerstone of quality assurance and method validation in clinical testing labs in the UK, ensuring that the results of patient investigations are reliable and comparable wherever they are produced. In this article we focus specifically on EQA for laboratories performing trace element measurements, although many of the points are applicable to the wider pathology areas.<\/p>\n

by S.-J. Bainbridge and Dr C. F. Harrington<\/strong><\/p>\n

Introduction<\/strong>
External Quality Assessment (EQA), also termed proficiency testing (PT), involves the regular distribution of test materials to participating laboratories so that they may evaluate their analytical performance against a peer-group, detect any accuracy or other problems that may develop with the assay and so improve the results that they produce. The key elements that differentiate EQA from PT include: education and support; identification of method poor performance; and method evaluation [1].<\/p>\n

Historically clinical science was one of the first disciplines to realize the usefulness of EQA and take steps to implement schemes that would be of use in the hospital laboratory. The first proficiency survey of UK clinical pathology laboratories was reported in 1953 and revealed a wide spectrum of results for the common tests [2]. Further surveys in the 1950s and 60s confirmed the need for regular PT. In 1969, the National Quality Control Scheme was initiated by the Wolfson Research Laboratories, Birmingham and involved the distribution of specimens every 14 days [2]. This is now known as the UK National External Quality Assessment Scheme (UKNEQAS) and is responsible for about 30 different schemes.<\/p>\n

In 2013, the importance of EQA in the NHS pathology services was emphasized by Dr Ian Barnes in a Department of Health review into quality assurance [3]. The review assessed current NHS quality assurance frameworks and governance mechanisms for pathology services. It gathered a diverse range of evidence: examining expectations of pathology services; identifying areas for improvement; and recommending a system-wide way forward. It recommended strengthening and standardizing the current quality assurance structures that are in place, which are based on the Royal College of Pathologists (RCPath) Joint Working Group for Quality Assessment (JWGQA), which co-ordinates and oversees the standards and performance of EQA schemes for all schemes regardless of provider.<\/p>\n

EQA for trace elements<\/strong>
The Trace Elements External Quality Assessment Scheme (TEQAS), which is part of UKNEQAS but based in Guildford, UK, was established in 1979 with distribution of specimens on a monthly schedule to UK hospital laboratories measuring copper and zinc in serum. During the next five years the scheme developed with inclusion of other participants and the introduction of additional analytes and specimen types. Following an international conference on Aluminium and Renal Disease in 1986, a two year arrangement was established with the EU Commission to fund participation in the serum aluminium programme for European laboratories involved with the monitoring of patients with chronic renal failure. An outcome of this work was the realization that analytical standards of performance for this measurement were very poor. In collaboration with the UK Department of Health it was proposed that the scheme should be linked to UKNEQAS in order to provide a mechanism for referral of poor performers to the Clinical Chemistry Advisory Panel. This link was formally established by the Advisory Committee on Analytical Laboratory Standards in 1988. The aims of TEQAS are consistent with the intentions of UK NEQAS, to:<\/p>\n