ISO/DIS 25459:2026

This Standard specifies requirements for determining commutability of CRMs of higher metrological order and the content of their supporting documentation that comply with the requirements of ISO 17511 and ISO 15194. This standard is applicable to commutable CRMs intended for use as secondary calibrators or international conventional calibrators in the m.3 position of calibration hierarchies described in ISO 17511, or for applications as trueness controls. This standard applies primarily to secondary commutable calibrator CRMs with assigned property values where the property has a magnitude that can be expressed as a quantitative scalar number or ratio to a reference or refers to a counting scale as also described in the scope of ISO 17511. When a secondary commutable CRM includes multiple measurands, this Standard is applied to each of the measurands present in the CRM. This standard also specifies requirements for including a correction for noncommutability bias in the calibration hierarchy of a particular measurement procedure (MP) when a CRM intended to be used as a commutable calibrator is not commutable with clinical samples when measured using a particular MP.