Overview
CEN ISO/TS 7013:2025 (identical to ISO/TS 7013:2023) - "Water quality - Guidance and requirements for designing an interlaboratory trial for validation of analytical methods" - provides practical requirements and recommendations for planning and running interlaboratory comparisons used to validate new standardized analytical methods in water analysis. It covers organizational preconditions, sample preparation and stability, participation rules, statistical evaluation, documentation and reporting. The Technical Specification is based on ISO 5725‑1 and ISO 5725‑2 and is focused on method validation (not proficiency testing).
Key topics and technical requirements
- Scope: Validation of physical, chemical and biochemical analytical methods for water quality; final validation step before standardization.
- Preconditions: Method development and stepwise validation (e.g., per ISO/TS 13530) completed before the interlaboratory trial. Participants must follow the standardized protocol without technical alterations.
- Participation:
- Minimum requirement: 24 outlier‑free data points from at least 8 laboratories.
- Recommended to register ≥12 laboratories to ensure robust results after outlier rejection.
- Samples and logistics:
- Organizer prepares and distributes the same sample material to all participants within the sample stability period.
- All registered participants should receive and, where possible, test all samples to maximise usable data.
- Method options:
- Allows evaluation of non‑crucial method options (e.g., alternative extraction variants) with documented pre‑normative validation; crucial changes (e.g., switching analytical principle) are excluded.
- Experts decide whether to pool or separate data sets from method options.
- Statistical evaluation: Follows ISO 5725 principles to determine repeatability and reproducibility and to calculate performance data.
- Documentation & reporting: Includes checklists, timetables and performance reporting (see Annex A for guidance).
Practical applications and users
- Applications:
- Final validation and performance evaluation of new standardized analytical methods for water monitoring, environmental laboratories, regulatory methods and research studies.
- Preparation of method performance data (repeatability, reproducibility) required for standard publication or regulatory acceptance.
- Who uses it:
- Standardization bodies and technical committees
- Interlaboratory trial organizers and coordinators
- Environmental and water analysis laboratories participating in method validation trials
- Accreditation and regulatory authorities reviewing method fitness‑for‑purpose
Related standards
- ISO 5725‑1 / ISO 5725‑2 - accuracy, repeatability and reproducibility (basis for statistical methods)
- ISO/TS 13530 - validation of individual measurement steps (referenced as a precondition)
- Note: ISO/IEC 17043 and ISO 13528 focus on proficiency testing and ARE NOT substitutes for method‑validation interlaboratory comparisons.
Keywords: water quality, interlaboratory trial, method validation, ISO/TS 7013, CEN ISO/TS 7013:2025, reproducibility, repeatability, analytical methods, sample stability, statistical evaluation.