The international harmonized protocol for the proficiency testing of (chemical) analytical laboratories (Technical Report)

Pure and Applied Chemistry

et al. 2011

139

This IUPAC study aims at formulating recommendations concerning the metrological traceability of a measurement result in chemistry. It is intended to provide the chemical measurement community with a consistent view of the creation, meaning, and role of metrological traceability and its underpinning concepts. No distinction is made between measurement results obtained in "high metrology" and in the "field". A description is given of the calibration hierarchies needed in different circumstances to arrive at metrological traceability along a metrological traceability chain. Flow charts of generic calibration hierarchies are presented as well as a variety of examples. The establishment, assessment, and reporting of metrological traceability are discussed, including the provision of metrological references by a metrological institutional framework and the role of interlaboratory comparisons.

Section: Purposes Of An Ilcmentioning

confidence: 99%

Metrological traceability of measurement results in chemistry: Concepts and implementation (IUPAC Technical Report)

Bièvre¹,

Dybkær

Pure and Applied Chemistry

et al. 2011

139

“…It follows that scores based on the observed participant standard deviation should not be applied in such a case. If a PT provider can set a normative population standard deviation r p on fitness-for-purpose grounds, z-scores, which compare a result bias from the assigned value with r p , can be calculated in a small scheme in the same manner as recommended in [1][2][3][4] for a large scheme. The condition is only that the standard uncertainty of the assigned value u cert is insignificant in comparison to r p (u cert 2 <0.1r p 2 ).…”

Section: Approachmentioning

confidence: 99%

“…The International Harmonized Protocol for the proficiency testing (PT) of analytical chemistry laboratories adopted by the International Union of Pure and Applied Chemistry (IUPAC) in 1993 [1] has been revised in 2006 [2]. Statistical methods for use in PT [3] have been published as a complementary standard to ISO/ IEC Guide 43, which describes PT schemes based on interlaboratory comparisons [4].…”

Section: Introductionmentioning

confidence: 99%

Implementation of proficiency testing schemes for a limited number of participants

Belli

Ellison²,

et al. 2007

Accred Qual Assur

A metrological background for the selection and use of proficiency testing (PT) schemes for a limited number N of laboratories-participants (less than 20-30) is discussed. The following basic scenarios are taken into account: (1) adequate matrix certified reference materials (CRM) or in-house reference materials (IHRM) with traceable property values are available for PT use as test items; (2) no appropriate matrix CRM is available, but a CRM or IHRM with traceable property values can be applied as a spike or similar; (3) only an IHRM with limited traceability is available. The discussion also considers the effect of a limited population of PT participants N p on statistical assessment of the PT results for a given sample of N responses from this population. When N p is finite and the sample fraction N/N p is not negligible, a correction to the statistical parameters may be necessary. Scores suitable for laboratory performance assessment in such PT schemes are compared.

“…The International Harmonized Protocol for proficiency testing (PT) of analytical chemistry laboratories adopted by IUPAC in 1993 [1] was revised in 2006 [2]. Statistical methods for use in PT [3] have been published as a complementary standard to ISO/IEC Guide 43, which describes PT schemes based on interlaboratory comparisons [4].…”

Section: Introductionmentioning

confidence: 99%

IUPAC/CITAC Guide: Selection and use of proficiency testing schemes for a limited number of participants—chemical analytical laboratories (IUPAC Technical Report)

Kuselman

Pure and Applied Chemistry

2010

A metrological background for implementation of proficiency testing (PT) schemes for a limited number of participating laboratories (fewer than 30) is discussed. Such schemes should be based on the use of certified reference materials (CRMs) with traceable property values to serve as PT items whose composition is unknown to the participants. It is shown that achieving quality of PT results in the framework of the concept "tested once, accepted everywhere" requires both metrological comparability and compatibility of these results.The possibility of assessing collective/group performance of PT participants by comparison of the PT consensus value (mean or median of the PT results) with the certified value of the test items is analyzed. Tabulated criteria for this assessment are proposed.Practical examples are described for illustration of the issues discussed.