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Impact of a common CV evaluation scheme on overall laboratory performance: 8-year experience of a large national proficiency testing program in Japan

Impact of a common CV evaluation scheme on overall laboratory performance: 8-year experience of a... Abstract In proficiency testing (PT), it is difficult to set rational criteria for determining target values and allowable limits. In Japan, the largest national PT program has for the past 8years used an evaluation scheme based on a “common coefficient of variation” (cCV) to overcome this difficulty. The cCV, the average within-method variation, is derived by one-way analysis of variance from data of peer groups after excluding those with large variations. A unit interval used for grading participants is obtained by multiplying the cCV by the peer-group mean which is computed using an iterative method featuring repeated removal of a large portion of the tails of the distribution and reinflation of the standard deviation (SD) to compensate for the trimming. The evaluation scheme gives a relatively better grade to those participants in peer groups with small CVs, compared to use of individual peer-group CVs. The scheme has expedited the transition to more reproducible methods, resulting in a notable overall improvement in laboratory performance. The cCV evaluation scheme is uniformly applicable to any analyte measured quantitatively. The iterative method, an integral part of the scheme, effectively precludes bias in the evaluation. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Clinical Chemistry and Laboratory Medicine (CCLM) de Gruyter

Impact of a common CV evaluation scheme on overall laboratory performance: 8-year experience of a large national proficiency testing program in Japan

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References (14)

Publisher
de Gruyter
Copyright
Copyright © 2005 by the
ISSN
1434-6621
eISSN
1437-4331
DOI
10.1515/CCLM.2005.075
pmid
15899659
Publisher site
See Article on Publisher Site

Abstract

Abstract In proficiency testing (PT), it is difficult to set rational criteria for determining target values and allowable limits. In Japan, the largest national PT program has for the past 8years used an evaluation scheme based on a “common coefficient of variation” (cCV) to overcome this difficulty. The cCV, the average within-method variation, is derived by one-way analysis of variance from data of peer groups after excluding those with large variations. A unit interval used for grading participants is obtained by multiplying the cCV by the peer-group mean which is computed using an iterative method featuring repeated removal of a large portion of the tails of the distribution and reinflation of the standard deviation (SD) to compensate for the trimming. The evaluation scheme gives a relatively better grade to those participants in peer groups with small CVs, compared to use of individual peer-group CVs. The scheme has expedited the transition to more reproducible methods, resulting in a notable overall improvement in laboratory performance. The cCV evaluation scheme is uniformly applicable to any analyte measured quantitatively. The iterative method, an integral part of the scheme, effectively precludes bias in the evaluation.

Journal

Clinical Chemistry and Laboratory Medicine (CCLM) – de Gruyter

Published: Apr 1, 2005

Keywords: between-method coefficient of variation; iterative method; proficiency testing; target value; within-method coefficient of variation

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