Guides

Guides

Current Eurachem Guides

The Fitness for Purpose of Analytical Methods (2025)

Full title

The Fitness for Purpose of Analytical Methods: A Laboratory Guide to Method Validation and Related Topics: Third edition (2025)

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Introduction

Frontcover Validation Guide 90

This guide was first issued in 1998 and the second edition published in 2014. Over the years it has been one of the most popular of the Eurachem guides. Since the release of the first edition, however, there have been many changes in terminology, working practices, reference documents and requirements. This third edition, produced by the Eurachem Method Validation Working Group, forms a thorough revision of the 2014 edition.

This third edition includes a section on sampling and sample handling as ISO/IEC 17025:2017 introduced a focus on sampling associated with the testing or calibration being carried out by the laboratory and further guidance on assessing the calibration function has been included. The Guide is also now supported by a number of supplementary guidance documents – please see the section on supplementary guidance below.

Contents

This third edition includes guidance on:

  • The importance of fitness for purpose;
  • The concept of method validation and verification;
  • How a method validation or verification study should be performed and how much should be done;
  • Sampling and sample handling in relation to method validation;
  • A thorough explanation of the various validation parameters (performance characteristics) and related topics;
  • Follow-up on the validation study (reporting, use of performance data in Internal Quality Control);
  • Documentation of analytical methods.

 

Annexes also describe the statistical basis of detection limits and analysis of variance for precision studies, and add a check list to aid users in selecting and determining the validity of a test kit.

In preparing this guidance, the Working Group has aimed at the right balance between giving a solid theoretical background for method validation studies and providing practical guidelines on how to plan, perform and evaluate such studies in the laboratories.

The approach is generic in the sense that the Guide does not focus on particular fields of application (food, environment, pharmaceuticals etc.). However, the guide includes references to a number of specific guides in fields where different practices have been developed and become common.

The guide also includes a full bibliography. Further literature references on method validation can be found in the section "Validation of analytical methods" in the Reading list on this website.

Availability

You can download the Guide here at no cost:

The second edition of this Guide is available in a number of translations. For details see previous editions below.

Citation

This publication should be cited* as:
"H. Cantwell (ed.) Eurachem Guide: The Fitness for Purpose of Analytical Methods – A Laboratory Guide to Method Validation and Related Topics, (3rd ed. 2025). Available from http://www.eurachem.org"

*Subject to journal requirements

Supplementary guidance

The supplementary guidance below gives additional guidance on method validation topics:

  • Planning and reporting method validation studies. This supplement is in the form of a template which can be used to assist with planning the evaluation of the chosen performance characteristics
  • Blanks in method validation. This short supplement describes the different types of blanks which may be used during method validation and provides guidance for situations where it may be difficult to obtain a suitable blank matrix.

Translations

Translation into other languages is permitted for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Previous version

The 2014 edition of this guide can be found here for reference.

 

Quality Assurance for Research and Development and Non-routine Analysis (1998)

Contents

This guide, produced by a joint Eurachem/CITAC working party representing industrial, academic, and governmental interests, promotes and describes the concepts of quality assurance in the non-routine environment. The guide promotes a nested approach to quality assurance, dealing with it at a general organisational level, a technical level and a project specific level. It is intended to promote the use of QA as an effective tool for establishing and maintaining quality in R&D and non-routine operations. It does not seek to set criteria for accreditation of R&D although there is a section describing various methods for third party assessment of quality systems. The guidance may form the basis on which accreditation criteria can be set in the future. The guidance is intended to complement the existing CITAC guide (CG1) which describes QA in the routine environment. It is primarily directed towards analytical chemistry establishments but is, in principle, applicable to other sectors. An extensive bibliography is included.

Availability

The English language version (edition 1.0 1998) is available from the UK National Measurement System Chemical and Biological Metrology programme.

Download the guide from this website (new window) (pdf, 203 kB).

Translations

A German language version can be downloaded from the Eurachem/DE website documents page. (Opens new Browser window).

Translation into other languages is permitted for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Harmonised Guidelines for the Use of Recovery Information in Analytical Measurements (1998)

This guide was produced by IUPAC with contributions from Eurachem.

Contents

It is recognised that the use of recovery information to correct/adjust analytical results is a contentious one for analytical chemists. Different sectors of analytical chemistry have different practices. Formal legislative requirements with regard to the use of recovery factors also vary sector-to-sector. It is the aim of IUPAC, however, to prepare general Guidelines which may be seen to aid the preparation of the “best estimate of the true result” and to contribute to the comparability of the analytical results reported. IUPAC Interdivisional Working Party on Harmonisation of Quality Assurance Schemes for Analytical Laboratories has co-operated with the International Organisation for Standardisation (ISO), the International Association of Official Analytical Chemists (AOAC Int.) and Eurachem to produce this guide. On the basis of contributions presented at the Symposium on Harmonisation of Quality Assurance Systems for Analytical Laboratories dedicated to the “Use of Recovery Factors in Analytical Chemistry” (September 1996, Orlando, USA; sponsored by IUPAC, ISO and AOAC Int.) a final document was prepared for publication by M. Thompson, S. L. R. Ellison, A. Fajgelj, P. Willetts and R. Wood. The document was submitted for publication in Pure and Applied Chemistry.
This document attempts to give Guidelines that are intended to be general in their scope and give recommendations that reflect common practice best able to achieve the comparability of analytical results. However, specific sectors of analytical chemistry will need to develop these Guidelines for their own requirements and the recommendations are not, therefore, to be seen as binding for all areas of analytical chemistry.

Availability

An English language version is available from A. Fajgelj, Quality Assurance Supervisor, International Atomic Energy Agency, Agency's Laboratories Seibersdorf, 2444 Seibersdorf, Austria. Tel.: +43 1 2600 28233, Fax: + 43 1 2600 28222, E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.. Alternatively, you may download the guide from this website (pdf, 73 kB).

Translations

No other translations are currently available.

Measurement uncertainty arising from sampling (2nd edition, 2019)

Full title

UfS CoverMeasurement uncertainty arising from sampling: A guide to methods and approaches
Second edition (2019)

Contents

This Guide aims to describe various methods that can be used to estimate the uncertainties arising from the processes of sampling and the physical preparation of samples. It is intended primarily for specialists such as sampling planners and for analytical chemists who need to estimate the uncertainty associated with their measurement results.

The Guide deals with the case where the measurand is defined in term of the value of the analyte concentration in a sampling target, rather than in just the sample delivered to the laboratory. In this case, the sampling process affects the result and its uncertainty, and sampling is necessarily considered as part of the measurement process. This Guide takes a holistic view of the measurement process to include sampling and sample preparation as well as the analytical process.

The Guide begins by explaining the importance of the total uncertainty in a measurement for making reliable interpretation of measurements, and judging their fitness for purpose. It covers the whole measurement process, defining each of the component steps, and describing the effects and errors that cause uncertainty in the final result, with particular attention to sampling issues.

Two main approaches to the estimation of uncertainty from sampling are described. The empirical approach uses repeated sampling and analysis, under various conditions, to quantify the effects caused by factors such as the heterogeneity of the analyte in the sampling target and variations in the application of one or more sampling protocols, to quantify uncertainty (and usually some of its component parts). The modelling approach uses a predefined model that identifies each of the component parts of the uncertainty, making estimates of each component, and sums them in order to make an overall estimate.

For either approach, the Guide follows the principles of the ISO Guide to the Expression of Uncertainty in Measurement, interpreted for analytical measurement in the Eurachem guide "Quantifying Uncertainty in Analytical Measurement" which is available here.

This Second Edition includes a number of additions and changes. These include

  • the expression of uncertainty of measurement as an 'uncertainty factor' (FU) when the frequency distribution describing the sampling uncertainty is log-normal rather than normal, and guidance on the use of an uncertainty factor in an uncertainty budget.
  • the use of an unbalanced design to estimate uncertainty more cost-effectively than can be achieved using the balanced ‘duplicate method’ design;
  • updates to definitions and references to reflect current international documents and literature, including applications of these methods to on-site and in situ measurements, made at both the macro and the micro scale.

Availability

From this website:

* Also available from the ISS website.

Additional translations:

Note: In parallel with this Eurachem Guide on sampling uncertainty, Nordtest developed a shorter handbook on sampling, which is available from the Nordtest website.

Editorial corrections

A small number of editorial corrections have been identified since the edition above was approved. These are listed in the sheet of Errata below.

Note: The Spanish edition (UfS:2019.P2-ES) published 2021-05-25 includes the corrections listed in the above correction list, up to errata version 1.2.

Citation

This Guide should be cited* as:

M H Ramsey, S L R Ellison and P Rostron (eds.) Eurachem/EUROLAB/ CITAC/Nordtest/AMC Guide: Measurement uncertainty arising from sampling: a guide to methods and approaches. Second Edition, Eurachem (2019). ISBN (978-0-948926-35-8). Available from http://www.eurachem.org

*Subject to journal requirements.

Translations

Translation into other languages is permitted for members of Eurachem. Other offers of translation should be directed to the Eurachem Secretariat for permission. The Eurachem policy on maintenance and development of Eurachem guidance, available on the Policies page, gives further information on translation.

Translations of the First edition can be found in the publication archive, here.