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Estimates of uncertainty of measurement from proficiency testing data: a case study

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Abstract

The results obtained by a laboratory over a number of proficiency testing/external quality assessment schemes (PT/EQAS) rounds can give information on the uncertainty of its measurements for a given test, provided that conditions such as full coverage of the routine analytical range, traceability, and small uncertainty of the assigned values (compared to the spread of the results) are met and provided that systematic deviations and any other sources of uncertainty are considered. As organisers of the Italian EQAS (ITEQAS) in occupational and environmental laboratory medicine, we tested this hypothesis using as model data from well-performing laboratories taking part in ITEQAS for lead in blood over the last 2 years. We also investigated how different PT/EQAS features (frequency of trials and number of samples) would affect a laboratory estimate of its uncertainty. Such information can be helpful in improving PT/EQAS organisation and define, for a given test: (a) the state of the art of the uncertainty of current measurement procedures, (b) identify needs for improvement of analytical methodologies and (c) set targets for acceptable uncertainty values.

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Acknowledgements

The authors acknowledge the financial support from the Italian Ministry of Health, Project “Analysis of risk connected with the presence of residues in food of animal origin - SARA”, 2003–2006.

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Authors and Affiliations

  1. Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy

    Marina Patriarca, Ferdinando Chiodo, Marco Castelli & Antonio Menditto

Authors
  1. Marina Patriarca
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  2. Ferdinando Chiodo
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  3. Marco Castelli
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  4. Antonio Menditto
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Corresponding author

Correspondence to Marina Patriarca.

Additional information

Presented at the Eurachem PT Workshop September 2005, Portorož, Slovenia.

Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher.

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Patriarca, M., Chiodo, F., Castelli, M. et al. Estimates of uncertainty of measurement from proficiency testing data: a case study. Accred Qual Assur 11, 474–480 (2006). https://doi.org/10.1007/s00769-006-0170-4

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  • DOI: https://doi.org/10.1007/s00769-006-0170-4

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