ASTM E1301-95e1
(Guide)Standard Guide for Proficiency Testing by Interlaboratory Comparisons
Standard Guide for Proficiency Testing by Interlaboratory Comparisons
SCOPE
1.1 While there are a number of uses for interlaboratory tests, and variations in their design and implementation, it is still possible to specify the essential principles that need to be considered when organizing such tests. Part A of this guide defines those principles and describes the factors that should be taken into account in the organization and conduct of proficiency testing programs.
1.2 This guide also covers how laboratory accrediting bodies, which assess technical competence of testing laboratories, should select and use proficiency testing programs (refer to Part B).
1.3 Part A of the guide is intended for use by various parties, such as accrediting bodies, regulatory authorities and clients of laboratory services which have a need to assess the technical competence of laboratories. It is also useful for laboratories in self-evaluation, but recognizes that proficiency testing is only one mechanism that can contribute to establishing equivalent confidence among users of different testing laboratories.
1.4 It is currently a condition of some accreditation bodies that laboratories participate regularly in "approved" proficiency testing programs. Therefore, it is essential that program operators comply with principles for conduct of professionally managed proficiency programs, both in terms of technical requirements and quality management (see Annexes A1 and A2).
1.5 The methods of operation within different proficiency testing organizations are not expected to be identical and this guide does not give specific operational details for interlaboratory test comparisons. It does, however, cover both measurement comparison and testing programs in which large numbers of laboratories (over 20) or small groups of laboratories (1 to 20) are tested. Therefore, the contents of this guide are intended only as a framework to be modified appropriately for particular situations.
1.6 A list of some relevant references is given in Appendix X1.
General Information
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Standards Content (Sample)
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An American National Standard
ϵ1
Designation: E 1301 – 95
Standard Guide for
Proficiency Testing by Interlaboratory Comparisons
This standard is issued under the fixed designation E 1301; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (ϵ) indicates an editorial change since the last revision or reapproval.
ϵ NOTE—Annex A3 was deleted editorially in March 1998.
INTRODUCTION
Proficiency testing is the use of interlaboratory test comparisons to determine the performance of
individual laboratories for specific tests and to monitor the consistency and comparability of a
laboratory’s test data.
Interlaboratory test comparisons are conducted for a number of other purposes including:
(1) Check the consistency and comparability of data for individual testing personnel;
(2) Assist in maintaining the calibration of instrumentation;
(3) Establish the effectiveness and comparability of new test methods;
(4) Achieve commercial improvement;
(5) Assist in determining reasons for interlaboratory differences;
(6) Determine the precision of a test method—often known as interlaboratory studies (see Practice
E 691E 691), collaborative trials, or round-robins; and
(7) Assign values to certified reference materials (CRMs).
Participation in proficiency testing programs provides laboratories with an objective means of
assessing and demonstrating the reliability of the data they are producing.Although there are several
types of proficiency testing programs, they all share the common feature of the comparison of test
results obtained by two or more laboratories.
One of the main uses of proficiency testing programs is to assess laboratories’ ability to perform
tests competently. It thus supplements laboratories’ own internal quality control procedures by
providing an additional external evaluation of their testing capability. These activities also comple-
mentthetechniqueofon-sitelaboratoryassessmentbytechnicalspecialistsusuallyusedbylaboratory
accrediting bodies. Confidence that a testing or calibration laboratory consistently obtains reliable
results is of major importance to users of laboratory services. Users seeking such an assurance may
undertake their own evaluation or may use the evaluation of other bodies.
Bodies assessing the technical competence of testing laboratories normally require or expect
satisfactory participation in proficiency testing as evidence of a laboratory’s ability to produce reliable
test results, except where proficiency testing is inappropriate. However, it is emphasized that a major
distinction exists between:
(1) Theevaluationofthecompetenceofalaboratorybytheassessmentofitstotaloperationagainst
pre-determined requirements, and
(2) The examination of the results of a laboratory’s participation in proficiency testing which may
only be considered as giving information about the technical competence of the testing laboratory at
a single point of time under the specific conditions of the test for tests involved in a particular
proficiency testing program.
1. Scope
1.1 While there are a number of uses for interlaboratory
This guide is under the jurisdiction of ASTM Committee E-36 on Laboratory
tests, and variations in their design and implementation, it is
Accreditation and is the direct responsibility of Subcommittee E36.60 on Accredi-
still possible to specify the essential principles that need to be
tation Systems.
considered when organizing such tests. Part A of this guide
Current edition approved October, 10, 1995. Published January 1996. Originally
published as E 1301 – 89. Last previous edition E 1301 – 89.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
ϵ1
E1301–95
definesthoseprinciplesanddescribesthefactorsthatshouldbe 3. Terminology
taken into account in the organization and conduct of profi-
3.1 Definitions—For formal definitions related to laboratory
ciency testing programs.
accreditation, Terminology E 1187E 1187 applies. For formal
1.2 This guide also covers how laboratory accrediting bod-
definitions related to quality and statistics, Terminology
ies, which assess technical competence of testing laboratories,
E 456E 456 applies. In addition, the following terms and their
should select and use proficiency testing programs (refer to
definitions are provided for ease of reference.
Part B).
3.1.1 accuracy—the closeness of agreement between a test
1.3 PartAoftheguideisintendedforusebyvariousparties,
result and an accepted reference value (Terminology
such as accrediting bodies, regulatory authorities and clients of
E 456E 456 without the note).
laboratory services which have a need to assess the technical
3.1.2 bias—the difference between the population mean of
competence of laboratories. It is also useful for laboratories in
the test results and an accepted reference value (Terminology
self-evaluation, but recognizes that proficiency testing is only
E 456E 456 without the discussion).
one mechanism that can contribute to establishing equivalent
3.1.3 certified reference material (CRM)—a reference ma-
confidence among users of different testing laboratories.
terial, accompanied by a certificate, one or more of whose
1.4 It is currently a condition of some accreditation bodies
property values are certified by a procedure that establishes
that laboratories participate regularly in “approved” profi-
traceability to an accurate realization of the unit in which the
ciency testing programs. Therefore, it is essential that program
property values are expressed, and for which each certified
operators comply with principles for conduct of professionally
value is accompanied by an uncertainty at a stated level of
managed proficiency programs, both in terms of technical
confidence (ISO Guide 30 without the notes).
requirements and quality management (see Annex A1 and
3.1.4 precision—the closeness of agreement between test
Annex A2).
results obtained under prescribed conditions (Terminology
1.5 The methods of operation within different proficiency
E 456E 456 without the three notes).
testing organizations are not expected to be identical and this
3.1.5 proficiency testing (laboratory)—determination of
guide does not give specific operational details for interlabo-
laboratory testing performance by means of interlaboratory
ratory test comparisons. It does, however, cover both measure-
comparisons (ISO/IEC Guide 2).
ment comparison and testing programs in which large numbers
3.1.6 reference material—a material or substance, one or
of laboratories (over 20) or small groups of laboratories (1 to
more of whose property values are sufficiently homogeneous
20) are tested. Therefore, the contents of this guide are
and well established to be used for the calibration of an
intended only as a framework to be modified appropriately for
apparatus, the assessment of a measurement method, or for
particular situations.
assigning values to materials (ISO Guide 30 without the note).
1.6 A list of some relevant references is given in Appendix
X1. 3.1.7 repeatability—the closeness of agreement between
test results obtained under repeatability conditions (that is,
2. Referenced Documents conditions under which test results are obtained with the same
test method in the same laboratory by the same operator with
2.1 ASTM Standards:
the same equipment in the shortest practical period of time
E 178 Practice for Dealing with Outlying Observations
usingtestunitsortestspecimenstakenatrandomfromasingle
E 456 Terminology Relating to Quality and Statistics
quantity of material that is as nearly homogeneous as possible
E 548 Guide for General Criteria Used for Evaluating
(Terminology E 456E 456 without the notes).
Laboratory Competence
3.1.8 reproducibility—the closeness of agreement between
E 691 Practice for Conducting an Interlaboratory Study to
test results obtained under reproducibility conditions (that is,
Determine the Precision of a Test Method
conditions under which test results are obtained with the same
E 1187 Terminology Relating to Laboratory Accreditation
test method on identical material in different laboratories
2.2 ANSI Standard:
(Terminology E 456E 456 without the notes).
ANSI/ISO/ASQC Q9000 Series: Quality Management and
3.1.9 test—technical operation that consists of determina-
Quality Assurance Standards
tion of one or more characteristics of a given product, process
2.3 ISO Standards:
or service according to a specified procedure (ISO/IEC Guide
ISO/IEC Guide 2, General Terms and Their Definitions
2).
Concerning Standardization and Related Activities
3.1.10 trueness—the closeness of agreement between the
ISO/IEC Guide 25, General Requirements for the Compe- population mean of the measurements or test results and an
tence of Calibration and Testing Laboratories
acceptedreferencevalue(TerminologyE 456E 456withoutthe
note).
ISO Guide 30, Terms and Definitions Used in Connection
with Reference Materials 3.2 Definitions of Terms Specific to This Standard:
3.2.1 accepted reference value—a value that serves as an
agreed-upon reference for comparison and which is derived as:
(1) a theoretical or established value, based on scientific
Annual Book of ASTM Standards, Vol 14.02.
principles, (2) an assigned value, based on experimental work
Available from American National Standards Institute, 11 W. 42nd St., 13th
Floor, New York, NY 10036. of some national or international organization, and ( 3)a
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
ϵ1
E1301–95
consensus value, based on collaborative experimental work also use proficiency testing programs or other forms of
under the auspices of a scientific or engineering group. interlaboratory tests operated by other bodies. The purpose of
3.2.2 Discussion—When the accepted reference value is the Part B of this guide is to provide harmonized principles for
theoreticalvalue,itissometimesreferredtoasthe“true”value. selection of suitable interlaboratory test programs for use as
(This is a small variation from the definition in Terminology proficiency testing programs by laboratory accreditation bod-
E 456E 456.) ies.
3.2.3 assigned value—estimate of the true value used in the
4.6 Part B of this guide is intended:
assessment of proficiency (also referred to as assigned refer-
4.6.1 To establish principles for the selection of proficiency
ence value).
testing programs for use in laboratory accreditation programs;
3.2.4 coordinator—person or body that coordinates all the
and
activities associated with a proficiency program.
4.6.2 To assist in harmonizing the use of results of profi-
3.2.5 internal quality control (IQC)—the set of procedures
ciency testing programs by laboratory accreditation bodies.
undertaken by a laboratory for continuous monitoring of
4.7 As results from proficiency testing programs may be
operations and results in order to decide whether the results are
used in accreditation decisions, it is important that both the
reliable enough to be released; IQC primarily monitors the
accrediting bodies and participating laboratories have confi-
batch-to-batch accuracy of results on quality control materials,
dence in the design and operation of the programs.
and precision on independent replicate analyses of test mate-
4.8 It is also important for participating laboratories and
rials.
laboratoryaccreditationassessorstohaveaclearunderstanding
3.2.6 outlier—an observation that appears to deviate mark-
of the accrediting bodies’ policies for participation in such
edly from the other observations of the sample (also referred to
programs; the criteria they use for judging successful perfor-
as extreme result, outlying or doubtful observation, or aberrant
mance in proficiency testing programs; and their policies and
value) (see Practice E 178E 178).
procedures for following up any unsatisfactory results from a
3.2.7 quality assurance system—the sum total of a labora-
proficiency test.
tory’s activities aimed at achieving the required standard of
4.9 It should be recognized that laboratory accrediting
analysis.
bodies and their assessors may take into account the suitability
3.2.8 reference laboratory—laboratory that establishes the
of test data produced from other activities apart from profi-
accepted reference value or assigned value.
ciency testing programs. This includes results of laboratories’
3.2.9 test item—material(s) or artifact(s) presented to the
own internal quality control procedures with control samples,
participating laboratory for the purpose of proficiency testing.
comparison with split-sample data from other laboratories,
3.2.10 testing laboratory—laboratory that performs tests
performance of one-time audit tests with certified reference
(including calibration) (also referred to as “participating labo-
materials, and so on. The use of data from these sources by
ratory” or just “laboratory”).
laboratory accrediting bodies is not covered by this guide.
However, the principles set out in this guide, regarding
4. Significance and Use
follow-up of unsatisfactory performance, could also apply to
4.1 The previous edition of this guide (E 1301 – 89) cov-
these activities.
ered the development and operation of laboratory proficiency
testing programs with limited, if any, emphasis on the use of
Part A: DEVELOPMENT AND OPERATION OF
the outcomes of proficiency testing by accreditation bodies.
PROFICIENCY TESTING PROGRAMS
4.2 This revised version is now intended to provide guid-
ance in three areas:
5. Types of Proficiency Testing
4.2.1 The introduction to this guide distinguishes between
5.1 Proficiency testing techniques vary depending on the
use of interlaboratory tests for proficiency testing and for other
nature of the item or material under test, the test method in use
purposes.
and the number of testing laboratories participating. They
4.2.2 Part A of this guide provides guidance on the devel-
possess the common feature of comparison of test results
opment and operation of interlaboratory tests for use in
obtained by one testing laboratory with those obtained by one
proficiency testing programs.
or more other testing laboratories. In some programs, one of
4.2.3 PartBofthisguideprovidesguidanceontheselection
the participating laboratories may have a controlling, coordi-
and use of proficiency testi
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