ISO 33400:2026

Overview

ISO 33400:2026, Reference materials - Vocabulary is an international standard developed by the International Organization for Standardization (ISO). This document provides a comprehensive set of terms and definitions crucial for the production, characterization, and use of reference materials (RMs), including certified reference materials (CRMs). Clear and consistent terminology is essential for laboratories, accreditation bodies, and organizations working with reference materials to ensure accuracy and reliability in measurement, calibration, and quality control processes.

ISO 33400:2026 replaces previous editions (such as ISO Guide 30:2015), offering updated definitions and a regrouped structure to align with current practices in reference material development and application worldwide.

Key Topics

• Reference Materials (RMs): Defined as materials, homogeneous and stable for one or more specified properties, which are established to be fit for a particular use.
• Certified Reference Materials (CRMs): A key subset of RMs, CRMs have one or more property values certified by a metrologically valid procedure, including statements of uncertainty and metrological traceability.
• Indicative Value: A value assigned to a property of a reference material that does not fully meet certification requirements, but is suitable for specific, defined uses.
• Reference Material Documentation: Includes reference material certificates for CRMs, product information sheets for non-certified RMs, and detailed production and certification reports.
• Production and Characterization: Terms cover all aspects of reference material production, the role of producers and subcontractors, and the steps involved in characterizing material properties, assessing homogeneity and stability, and assigning certified values.
• Use of Reference Materials: Guidance on intended use, period of validity, minimum sample size, and concepts such as commutability for ensuring application-related relevance of RMs.

Applications

ISO 33400:2026 ensures that everyone working with reference materials uses the same language, reducing ambiguity and supporting effective communication in:

• Calibration of Measuring Systems: RMs and CRMs are used to calibrate instruments across various fields, ensuring traceability and comparability of measurement results.
• Validation of Measurement Methods: Laboratories use RMs to verify that analytical procedures produce accurate and reliable results.
• Quality Control in Laboratories: Routinely applying RMs and CRMs helps laboratories monitor and maintain the precision and accuracy of their analyses.
• Accreditation and Compliance: Organizations seeking laboratory accreditation under ISO/IEC 17025 or ISO 17034 rely on standardized terminology to demonstrate compliance and technical competence.
• Harmonization of Testing: Internationally recognized terminology helps harmonize test results across borders and disciplines, ensuring shared understanding in inter-laboratory comparisons and proficiency testing.

Related Standards

Users of ISO 33400:2026 may also benefit from familiarity with these related ISO and IEC standards:

• ISO/IEC Guide 99: International vocabulary of metrology - Basic and general concepts and associated terms (VIM)
• ISO 17034: General requirements for the competence of reference material producers
• ISO 33401: Reference materials - Contents of certificates, labels, and accompanying documentation
• ISO 33403: Reference materials - Requirements and recommendations for use
• ISO 33405: Reference materials - Approaches for characterization and assessment of homogeneity and stability
• ISO 33406:2024: Production of reference materials with qualitative properties
• ISO/IEC 17000:2020: Conformity assessment - Vocabulary and general principles
• ISO 17511:2020: In vitro diagnostic medical devices - Requirements for establishing metrological traceability

Practical Value

Implementing ISO 33400:2026 supports:

• Consistent communication among producers, users, and assessors of reference materials
• Reliable laboratory calibration and quality assurance
• Facilitation of global trade by ensuring measurement comparability
• Confidence in laboratory results for regulatory, research, and industrial applications

For organizations involved in producing or utilizing reference materials, ISO 33400:2026 is an essential vocabulary resource supporting best practices and regulatory acceptance worldwide.