IJCA Vol 5 Issue 1 - Flipbook - Page 42
The International Journal of Conformity Assessment
2026 | Volume 5, Issue 1
Together, these clauses emphasize that
participation alone is insufficient. Laboratories
must actively assess comparison results,
investigate deviations, and document actions
taken. The standard therefore supports flexibility
in participation while maintaining a strong
expectation for technical evaluation and continual
improvement.
3.2 ILAC-P9:01/2024 — Policy Clarification and
Reinforcement
ILAC-P9:01/2024 builds upon the general
requirements of ISO/IEC 17025 by introducing
explicit, enforceable expectations for
proficiency testing and interlaboratory
comparison participation. While ISO/IEC
17025 defines what laboratories must achieve,
ILAC-P9 clarifies how accreditation bodies
are to assess compliance in practice.
Under ILAC-P9, participation in PT or suitable ILCs
is mandatory when such activities are available,
appropriate, and necessary. Laboratories are
required to conduct and document a risk-based
assessment to justify decisions regarding
participation, including the selection of activities
and the frequency of participation. This represents
a shift from discretionary participation toward
a structured, planned approach integrated
into the quality management system.
A central requirement of ILAC-P9 is the
development and maintenance of a documented
PT/ILC participation plan. This plan must
exist prior to accreditation and be maintained
throughout the accreditation cycle. It is expected
to define the scope of coverage, participation
strategy, technical justification, and actions to
be taken in response to unsatisfactory results.
ILAC-P9 also emphasizes the concepts of
availability and appropriateness. A PT scheme
may be available but technically unsuitable
due to mismatches in measurand, uncertainty
level, scope coverage, or evaluation method.
In such cases, laboratories are expected
to document technical justification for
alternative approaches rather than rely on
generalized statements of non-availability.
Accreditation bodies are required to review PT/
ILC participation plans during accreditation
and surveillance activities. This reinforces the
expectation that laboratories demonstrate
not only participation, but also informed
planning, technical understanding, and
effective use of comparison results.
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4. Implications of ISO/IEC 17043:2023 for
Calibration Laboratories
ISO/IEC 17043:2023 introduces substantive
revisions to the standard governing the
competence of proficiency testing providers.
Although directed primarily at PT providers,
these changes have important implications for
calibration laboratories that rely on PT results as
evidence of competence.
One significant development is the alignment
of ISO/IEC 17043:2023 with the structure and
principles of ISO/IEC 17025:2017. The revised
standard emphasizes impartiality, competence,
confidentiality, and consistent operations,
contributing to a more coherent conformity
assessment framework. For calibration
laboratories, this alignment supports greater
transparency and consistency in how PT schemes
are designed, operated, and evaluated.
ISO/IEC 17043:2023 also reinforces harmonization
with ISO 13528:2022, which provides statistical
guidance for proficiency testing by interlaboratory
comparison. The revised standard places greater
emphasis on the use of technically valid statistical
methods for determining assigned values,
evaluating participant performance, and reporting
results. As a result, calibration laboratories
should expect PT reports to include more
explicit information regarding evaluation criteria,
uncertainty treatment, and performance thresholds.
The revised standard strengthens requirements
