ISO 33401:2024

Overview

ISO 33401:2024 - Reference materials - Contents of certificates, labels and accompanying documentation - provides a clear framework for the documentation that must accompany reference materials (RMs) and certified reference materials (CRMs). Published by ISO as the first edition replacing ISO Guide 31:2015, this standard helps Reference Material Producers (RMPs) prepare concise, consistent product information sheets, RM certificates, and unit labels so users can confirm an RM’s suitability for calibration, quality control, method validation and other measurement activities.

Key topics and requirements

ISO 33401:2024 defines mandatory, recommended and additional information to include in RM documents and labels. Major technical topics covered include:

• Document types: product information sheet (for RMs) and reference material certificate (for CRMs).
• Identification: title, unique identifier and RM name.
• Producer details: name and contact details of the reference material producer (RMP).
• Intended use and minimum sample size for measurement.
• Period of validity, storage information, and instructions for handling and use.
• Commutability (where applicable) and other material-specific attributes.
• Measurement information: measurement procedures for operationally defined measurands, property of interest, property values and associated measurement uncertainty.
• Metrological traceability statement and authorization (name/function of approving officer).
• Supplementary information: health & safety, subcontractors, indicative values, legal notices and references to certification reports.
• Labels: minimum requirements for the label attached to an individual RM unit.

The standard aligns with and supports implementation of ISO 17034 requirements for RM production.

Practical applications

ISO 33401 is used to:

• Create standardized RM certificates and product information sheets that enable traceable, reproducible measurements.
• Help laboratories, calibration providers and proficiency testing organisers verify the fitness-for-purpose of an RM or CRM.
• Improve transparency for customers and accreditation bodies by documenting uncertainty, traceability and handling requirements.
• Support quality assurance in sectors relying on RMs: clinical diagnostics, environmental testing, food safety, materials testing and metrology.

Who should use ISO 33401:2024

• Reference Material Producers (RMPs) preparing RM documentation and labels.
• Accreditation bodies and certification assessors reviewing RM documentation.
• Testing and calibration laboratories, proficiency testing providers, and end-users of RMs and CRMs.
• Quality managers responsible for measurement traceability and uncertainty reporting.

Related standards

• ISO 17034 - General requirements for the competence of RMPs.
• ISO Guide 30 - Selected terms and definitions for reference materials.

Keywords: ISO 33401:2024, reference materials, RM certificate, product information sheet, certified reference material, metrological traceability, measurement uncertainty, reference material producer.