Procedure validation has long been a standard practice for
calibration laboratories. However, the new revision of ISO/IEC 17025:2017 introduced
the term ‘Verification’. In Clause 184.108.40.206, the standard states “The laboratory
shall verify that it can properly perform methods before introducing them by
ensuring that it can achieve the required performance. Records of the
verification should be retained.”
Although the basic terminology was used in the ISO/IEC
17025:2005 version hidden in Clause 5.4.2, ‘The laboratory shall confirm that
it can properly operate standard methods before introducing the tests or
calibrations”, a bigger emphasis has been placed on the verification process
and the documentation required.
What does this new term Verification mean and what is the
difference between Verification and Validation?
Calibration laboratories sometimes use the terms Validation
or Verification interchangeably, but they are not clear on the differences or
the circumstances of when they are required to be used. Most of the confusion
begins with the ISO 17025 standard definitions for the terms.
In ISO/IEC 17025:2005, Clause 220.127.116.11 states that “Validation
is the confirmation by examination and the provision of objective evidence that
the particular requirements for a specific intended use are fulfilled.”
In the newer ISO/IEC 17025:2017, Verification
is defined as “provision of objective evidence that a given item fulfills specified
requirements’, while Validation is defined as ‘verification, where the
specified requirements are adequate for an intended use”.
part of the new definition of Verification contains the same wording as the old
definition of Validation. To begin to unravel the meanings of the words, we
will begin with the method selection.
There are three basic types of
methods/procedures that can be used in a calibration laboratory; standard
methods, published procedures and laboratory-developed procedures.
Standard methods are methods published either in
international, regional or national standards, or by reputable technical
organizations, or in relevant scientific texts or journals.
Published procedures are procedures listed in other
published outlets and include manufacturer’s performance tests in manufacturer
service manuals and military procedures through GIDEP.
Laboratory-developed procedures are procedures written
within an individual calibration laboratory, typically when the information
required is not available in the documents listed above.
For most calibration laboratories, the
standard methods are not used as procedures. Standard publications such as
ASME, ANSI, ISO, etc. have specific information on equipment classifications
and specifications, but they typically do not contain true calibration
procedures. These methods are directed more towards testing laboratories rather
than calibration laboratories. For the majority of calibration laboratories,
either published procedures or laboratory-developed procedures are used.
methods and published
procedures are considered to be validated. That means that the method/procedure
has been proven to produce the stated measurement results when the procedure is
However, every calibration laboratory has
different equipment, competencies, and other factors that will determine what
capabilities the laboratory can maintain.
Due to this, “Verification” is required
for these methods/procedures to show that the laboratory is capable of
performing the procedure and are able to achieve the measurement values,
accuracy and other performance parameters of the procedure.
Verification needs to be documented and the procedure should be verified to
ensure that the laboratory has the required:
Equipment – The equipment used for the calibration should be equivalent in accuracy and scope as the recommended equipment in the procedure.
Environmental Conditions – The laboratory should have the proper environmental conditions for the performance of the procedure.
Personnel Competence – The personnel assigned to perform the procedure should have the necessary training and experience for the calibration.
new procedure is used that has just been developed by the laboratory, a “Validation”
is required to show that the procedure is capable of being performed and can meet the required specifications.
are required for all new
procedures or previously validated procedures that
require revisions because they’ve been significantly changed. A ‘re-validation’
would be required if significant changes were made to the procedure
methodology, equipment used in the procedure, specification or environmental
changes, or other conditions that could affect the results. This includes any
of the standard methods or published procedures listed above if there
are significant changes in how the
calibration laboratory is performing the procedure.
If changes are made to a specific section of a previously
validated procedure, only that section would need to be re-validated.
The extent of the Validation
should be developed with consideration of the costs, risks, customer
requirements, and the intended use of the results.
The Validation documentation
for the procedure should identify that the:
Proper equipment is listed – The equipment should be able to perform the calibration steps in the procedure.
Correct measurement values in tables or data forms – The calculated measurement values from the equipment specifications should be correct.
Calibration setup and connections are correct – Any diagrams or descriptions of the setup of the equipment needs to be correct.
Procedure steps produce the desired measurement outcome – The measurement values obtained during the validation should be what is required in the procedure.
It is important that the individual
who wrote the procedure should not be the person who validates the procedure. A
bias can be introduced if the same person performs the validation. The
validation should be performed by another competent technician certified in the
discipline of the piece of equipment the validation is being performed for.
To summarize, for a “Verification”,
the emphasis is on the calibration laboratory to ensure that it can
perform a standard or published procedure, whereas in a “Validation”, the
emphasis is that the procedure being validated can produce the required