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Clinical Chemistry and Laboratory Medicine (CCLM)

Published in Association with the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM)

Editor-in-Chief: Plebani, Mario

Ed. by Gillery, Philippe / Greaves, Ronda / Lackner, Karl J. / Lippi, Giuseppe / Melichar, Bohuslav / Payne, Deborah A. / Schlattmann, Peter


IMPACT FACTOR 2018: 3.638

CiteScore 2018: 2.44

SCImago Journal Rank (SJR) 2018: 1.191
Source Normalized Impact per Paper (SNIP) 2018: 1.205

Online
ISSN
1437-4331
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Volume 55, Issue 10

Issues

Expressing analytical performance from multi-sample evaluation in laboratory EQA

Marc H.M. Thelen
  • Corresponding author
  • Laboratory for Clinical Chemistry, Amphia Hospital, Postbox 90158, 4800RK, Breda, The Netherlands, Phone: +31765952030, Fax: +31765953807
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Rob T.P. Jansen
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Cas W. Weykamp
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Laboratory for Clinical Chemistry, Queen Beatrix Hospital, Winterswijk, The Netherlands
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Herman Steigstra
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Ron Meijer
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Christa M. Cobbaert
  • SKML, Organization for Quality Assurance of Medical Laboratory Diagnostics, Radboud University, Nijmegen, The Netherlands
  • Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-02-09 | DOI: https://doi.org/10.1515/cclm-2016-0970

Abstract

Background:

To provide its participants with an external quality assessment system (EQAS) that can be used to check trueness, the Dutch EQAS organizer, Organization for Quality Assessment of Laboratory Diagnostics (SKML), has innovated its general chemistry scheme over the last decade by introducing fresh frozen commutable samples whose values were assigned by Joint Committee for Traceability in Laboratory Medicine (JCTLM)-listed reference laboratories using reference methods where possible. Here we present some important innovations in our feedback reports that allow participants to judge whether their trueness and imprecision meet predefined analytical performance specifications.

Methods:

Sigma metrics are used to calculate performance indicators named ‘sigma values’. Tolerance intervals are based on both Total Error allowable (TEa) according to biological variation data and state of the art (SA) in line with the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Milan consensus.

Results:

The existing SKML feedback reports that express trueness as the agreement between the regression line through the results of the last 12 months and the values obtained from reference laboratories and calculate imprecision from the residuals of the regression line are now enriched with sigma values calculated from the degree to which the combination of trueness and imprecision are within tolerance limits. The information and its conclusion to a simple two-point scoring system are also graphically represented in addition to the existing difference plot.

Conclusions:

By adding sigma metrics-based performance evaluation in relation to both TEa and SA tolerance intervals to its EQAS schemes, SKML provides its participants with a powerful and actionable check on accuracy.

This article offers supplementary material which is provided at the end of the article.

Keywords: analytical performance specifications; bias; external quality assessment; imprecision

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About the article

Received: 2016-10-25

Accepted: 2016-12-20

Published Online: 2017-02-09

Published in Print: 2017-08-28


Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

Research funding: None declared.

Employment or leadership: None declared.

Honorarium: None declared.

Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.


Citation Information: Clinical Chemistry and Laboratory Medicine (CCLM), Volume 55, Issue 10, Pages 1509–1516, ISSN (Online) 1437-4331, ISSN (Print) 1434-6621, DOI: https://doi.org/10.1515/cclm-2016-0970.

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