Volume 5 · Issue 10 · October 2000
An Overview of the
Changes to Guide 25
ISO/IEC 17025: The Standard for Laboratory Competence
Many organizations that rely on the services of testing
and calibration laboratoriesespecially those required
by customers or industry requirements to use laboratories
with demonstrated competencehave heard the name ISO/IEC
17025 in the past year. But many are not quite sure what it
actually means to them and all other organizations and their
Although ISO/IEC 17025:1999, General requirements for
the competence of testing and calibration laboratories,
replaces ISO/IEC Guide 25:1990, which had almost the exact
same name, it is the first edition published as an International
This change in status from guide to standard is important,
because ISO/IEC 17025 is not only a bona fide standard, but
it is being viewed by many as such, whereas Guide 25 was perceived
to be only a guide not worthy of being followed. While the
automotive industry and some individual companies outside
the automotive sector have made use of Guide 25 accreditation
(e.g., Shell and DuPont), there are others that have expressed
an interest in using ISO/IEC 17025, especially in the food
industry. The US Food and Drug Administration (FDA) also has
announced it is pursuing accreditation of its labs.
The ISO Committee on Conformity Assessment (CASCO) undertook
its revisions of Guide 25 in 1994. Completion of CASCOs
work took five years because the issues that needed to be
addressed were many and difficult, but the result is a big
The standard has been unanimously adopted by more than 45
accreditation bodies that are members of the International
Laboratory Accreditation Cooperation (ILAC). These include
many European bodies, making ISO/IEC a significant development,
since Guide 25 was not used in Europe. European Norm (EN)
45001, which is slightly different from Guide 25, was until
recently the standard in use.
ISO/IEC 17025 by itself will also facilitate the effectiveness
of the ILAC mutual recognition arrangement (ILAC Arrangement),
which is expected to be signed by more than 30 national laboratory
accreditation bodies in early November 2000. The ILAC Arrangement
will provide a technical underpinning to international trade
by promoting cross-border stakeholder confidence and acceptance
of accredited laboratory data.
There is no international mutual recognition agreement yet
in lab accreditation, which can be a hindrance for some types
of international trade. ISO/IEC 17025 and the ILAC Arrangement
therefore fill a gap that has long existed.
Scope and Purpose of ISO/IEC 17025
ISO/IEC 17025:1999 is intended primarily for laboratories
that wish to demonstrate competence, whether or not they desire
accreditation. It also provides uniform general accreditation
criteria with numerous explanatory notes to reduce the need
for further application documents.
Besides Guide 25, the new standard has replaced the European
standard EN45001. It includes new requirements for the development
of new methods and method validation and sampling techniques
where such developments are relevant to a laboratorys
work. However, ISO/IEC 17025 does not address purely research
and development laboratories.
Even though the standard incorporates quality management
system (QMS) requirements equivalent to those in ISO 9001/2:1994,
it should not be characterized as a laboratory-specific QMS
It was never intended for "certification" in the ISO 9001/2/3
sense of quality system registration. ISO/IEC 17025 includes
technical requirements related to laboratory competence to
perform specific tests or calibrations. As such, the only
suitable form of recognition against it is accreditation for
the performing of specific tests or calibrations.
How Does It Differ From Guide 25?
Although there is some debate about what the major differences
are between the new standard and the superseded Guide 25,
the following paragraphs, numbered to correspond to the requirement
sections of ISO/IEC 17025:1999, provide a brief overview of
Your organization should actually examine the text of the
standard very carefully as a whole unit, especially if it
is unfamiliar with Guide 25. There is no simple list from
which you can conclude what a laboratory that has conformed
to Guide 25 actually needs to change and how to conform to
Keep in mind that this overview is designed for those familiar
with Guide 25, but it could be helpful for those organizations
that use calibration and/or testing laboratories, whether
or not they are in industrial sectors where the use of accredited
labs is or will be required.
4, Management Requirements
This section does not quite cover the complete requirements
of ISO 9001/2:1994. Some elements of ISO 9001/2 are addressed
in Section 5, Technical Requirements. Likewise, there are
also some "technical" aspects covered in this "management"
This clause covers ISO/IEC Guide 25:1990 items in
a similar way, but less prescriptively. A new requirement
is the need for a laboratory to identify any potential conflicts
of interest. Clause 4.1 recognizes that a laboratory acts
in many ways like a "third party" in that it is not in business
to simply satisfy its direct customers (i.e., always giving
customers the results they expect), but to provide valid,
reliable data upon which appropriate decisions can be made.
4.2, Quality System
Although the list of what the quality manual is
required to contain is less prescriptive, the required contents
of a laboratorys quality policy statement are more prescriptive.
4.3, Document Control
More specific requirements are included for the
review, approval, issuance and amendment of documents in line
with ISO 9001/2:1994.
4.4, Review of Requests, Tender and Contracts
Guide 25s contract review requirements were
"arrangements for handling new work". Those arrangements a
laboratory is to have for handling new work have been converted
to the ISO 9001/2 requirements, including identification of
customer needs, assurance to meet those needs and provision
for handling changes or deviations to contracts.
4.5, Subcontracting of Tests and Calibrations
This clause has been expanded to cover permanent
subcontracting of parts of the work involved in accredited
tests/calibrations, whereas Guide 25 only addressed temporary
4.6, Purchasing Services and Supplies
Quality control of services and suppliesor
inputs to a laboratorys processes affecting the integrity
of tests and calibrationsis now covered more comprehensively,
but yet in a slightly simpler fashion than ISO 9001/2:1994.
4.7, Service to the Client
This is a new clause with no prior counterpartGuide
25 did not address communicating with or servicing clients.
Cooperation with clients is demanded. Advising clients on
what they may really need from the testing to be conducted
is also encouraged. This is a notable change. While labs traditionally
are not uncooperative, advice has been perceived as potentially
representing a conflict of interest, so the new requirements
make cooperation and advice required or permissible.
A change is that it is no longer necessary to audit
the relevant operations when any complaint raises doubt about
the validity of the test/calibration results. Otherwise, the
requirements in this clause are equivalent to those in Guide
4.9, Control of Nonconforming Testing
and/or Calibration Work
A single requirement for a laboratory to have procedures
for control of nonconforming work has been introduced that
consolidates and replaces prior requirements found in several
clauses of Guide 25.
4.10, Corrective Action
This clause has been upgraded to be in line with
ISO 9001/2s content by requiring procedures to be implemented
for cause analysis, selection and implementation of corrective
action, subsequent monitoring and follow-up audits.
4.11, Preventive Action
This is a new requirement in line with ISO 9001/2s
4.12, Control of Records
Although very similar to the prior requirements,
it is written to be in line with ISO 9001/2s content.
It also addresses electronic records in an up-to-date fashion.
4.13, Internal Audits
Very similar to Guide 25s requirements, it
is in line with ISO 9001/2s content.
4.14, Management Review
This clause now specifies what must be addressed
by management reviews, but the absolute requirement that a
lab conduct annual reviews has been transformed into a recommendation
contained in a note.
5 Technical Requirements
The technical requirements are described in greater
detail than in Guide 25 to ensure more consistent interpretation
by laboratories and enlighten the reader about the intentions
of the requirements.
This clause lists the factors that determine the
correctness and reliability of results and the contributions
to the total uncertainty of measurements.
The requirements for personnel competency to be
used by a laboratory are much more clearly described. The
additional detail has slightly expanded the requirements.
5.3, Accommodations and Environmental
The requirements in this clause are very similar
to those in Guide 25.
5.4, Test and Calibration Methods and
This clause is greatly expanded to address nonroutine
work, validation of methods and estimation of uncertainty
of measurement. Although the measurement uncertainty concept
is well known to the calibration community, many fields of
testing are unfamiliar with the concept and its application
to tests, particularly tests whose results are qualitative.
This was the major reason for the US negative vote on the
FDIS. Much work is needed to develop examples of how to estimate
uncertainty for testing. For this reason, implementation will
take more time in some areas. A pragmatic, incremental approach
to the implementation of measurement uncertainty is being
recommended by many accreditation bodies.
These requirements are much the same as before,
except that sampling equipment and borrowed, rented or leased
equipment is now explicitly addressed.
5.6, Measurement Traceability
With the exception of Clause 5.10 below, which provides
reporting requirements, this clause is the only one that addresses
the distinctions between calibration laboratories and testing
laboratories. There are eight notes to explain certain aspects
of the requirements.
The requirements for sampling are new.
5.8, Handling of Test and Calibration
No major changes from Guide 25 are evident.
5.9, Assuring the Quality of Test and
No substantive changes have been made to these requirements.
5.10, Reporting the Results
A great deal more flexibility is allowed a laboratory
depending upon whether it issues calibration certificates
or reports and/or test reports and whether it services internal
or external clients. For internal clients and in the case
of written agreements with external clients, the results may
be reported in a simplified way. Opinions and interpretations
may also be included in a test report if properly identified
The first annex provides a table identifying where
the different elements of ISO 9001/2:1994 are addressed in
Guidelines for establishing applications in specific
fields are provided, with an admonition that applications
should not include additional general requirements.
The Transition to ISO/IEC 17025
Calibration and testing laboratories and their accreditation
bodies have entered a period of transition now that ISO/IEC
17025:1999 has been published and updating of the accreditation
process is underway. The challenge is for accreditation bodies
to revise processes and train staff and assessors on the new
standard while laboratories update their quality systems and
technical processes to the new and revised requirements. In
general, the sooner the transition is completed the better,
since the transition period will give rise to two types of
accreditationto the old Guide 25 and the new 17025.
One thing remains clear: if a laboratory is accredited to
the criteria of ISO/IEC Guide 25:1990, it remains competent.
Only the prerequisites have changed in line with the desire
of the community of interests to align management requirements
with ISO 9001/2:1994. Most accredited laboratories are expected
to conform to ISO/IEC 17025:1999 by 2002. As discussed above,
agreed practice for uncertainty estimation may take longer
in some fields of testing.
ILAC guidance on ISO/IEC 17025 implementation will be decided
at an ILAC General Assembly meeting in November 2000. The
current proposal is that, by the end of 2002, all laboratories
accredited to Guide 25 must be operating to the new standard
and must have been through a surveillance, assessment or re-assessment
by their accreditation bodies to confirm compliance.
Very few ISO/IEC 17025 accreditations have been accomplished
to date, and laboratories accredited to Guide 25 by the American
Association for Laboratory Accreditation (A2LA) have until
July 1, 2002, to comply based on a successful on-site assessment.
With completion of ISO/IEC 17025 in 1999 and its linkage
to the quality system requirements of ISO 9001/2:1994, the
transition to the new standard may barely finish before another
transition will begin. Recognizing the impending approval
of ISO 9001:2000 in November 2000, CASCO has already started
the work of considering an amendment to align ISO/IEC 17025:1999
with ISO 9001:2000. This revision work is clearly not expected
to take another six years. A two-year time frame is anticipated,
resulting in release of ISO/IEC 17025:2002 that will ensure
consistency of the QMS approaches between laboratories and
The elevation of laboratory competency requirements to the
status of an International (ISO/IEC) Standard has already
reaped benefits. The misinformed debate about a "standard
versus guide" is now over. There is no longer much confusion
in the laboratory marketplace as to the imperative nature
of the new standard and its use as accreditation criteria.
The widespread and quick adoption of ISO/IEC 17025:1999 by
the worlds laboratory accreditation body community and
many of their stakeholders has ensured its use and importance
as the basis of mutual recognition agreements for facilitating
trade. The standard represents a major milestone foreseen
23 years ago at the first International Laboratory Accreditation
If your organization uses or will need to use laboratories
accredited to Guide 25 or ISO/IEC 17025, it is advisable to
become familiar with the full text of the new standard. This
will help you understand what is or will be required of laboratories
to demonstrate competency and in providing services to your
Peter S. Unger is President of A2LA, a nonprofit membership
organization that administers the largest general purpose
laboratory accreditation system in the United States. He has
been involved with national laboratory accreditation since
1978. Prior to attaining his current position in 1996, Mr.
Unger served as Vice President of A2LA and was previously
Associate Manager of Laboratory Accreditation at the National
Bureau of Standards (now the National Institute of Standards
and Technology). He is also Chairman of the Mutual Recognition
Arrangement Council of the Asia Pacific Laboratory Accreditation
Cooperation (APLAC), chairs the Training Committee of the
National Cooperation for Laboratory Accreditation (NACLA)
and is Convenor of the Working Group on Arrangement Documentation
of ILAC. Mr. Unger has a BS degree in systems engineering
from Princeton University, a Masters in environmental management
from George Washington University, is an RAB-certified lead
auditor and is a member of THE OUTLOOKs Editorial
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