ISO 21151:2020 PDF

Overview

ISO 21151:2020 - In vitro diagnostic medical devices - Requirements for international harmonisation protocols establishing metrological traceability of values assigned to calibrators and human samples - specifies requirements for an international protocol that achieves equivalent results among two or more IVD medical devices (IVD MDs) for the same measurand when no reference measurement procedures or fit‑for‑purpose certified reference materials (CRMs) or international conventional calibrators exist. In such cases, the harmonisation protocol becomes the highest level of metrological traceability for the measurand. The standard addresses the specific traceability case described as 5.6 in ISO 17511:2020.

Key topics and technical requirements

• Scope and purpose
  • Defines when a harmonisation protocol is appropriate (no reference procedure and no fit‑for‑purpose CRM or calibrator).
  • Establishes the harmonisation protocol as the highest reference for traceability of assigned values.
• Measurand definition
  • Measurand shall be defined according to ISO 17511 principles.
• Specifications for agreement
  • Predefined, medically meaningful criteria for agreement among different IVD MDs at relevant concentrations/amounts.
• Inclusion/exclusion criteria for IVD MDs
  • Performance characteristics required for participation: precision, proportional recovery, selectivity, linearity and other clinically relevant metrics.
• Harmonisation reference materials
  • Requirements for materials used (e.g., panels or pools of human samples, supplemented samples, or other non‑certified preparations) and considerations about commutability and limited availability.
• Measurement and value assignment
  • Procedures for participants to measure reference materials and for assigning a single quantity value to each harmonisation reference material.
• Calibration hierarchy modification
  • How manufacturers adapt their calibration hierarchies to trace calibrators to the harmonisation protocol and assign values to calibration verification controls.
• Effectiveness and sustainability
  • Criteria to assess success, ongoing maintenance, and inclusion of additional IVD MDs over time.
• Documentation
  • Information on metrological traceability to be included in instructions for use.

Applications

• Standardizes numerical equivalence of patient results across different IVD devices where higher‑order references are unavailable.
• Enables consistent clinical decision limits and guideline application by ensuring results are comparable across platforms.
• Supports manufacturers, clinical laboratories, metrologists and regulators in implementing calibration strategies when CRMs or reference procedures are not fit‑for‑purpose.

Who should use this standard

• Harmonisation organizations and international standard bodies
• IVD medical device manufacturers and calibration laboratories
• Clinical laboratories and laboratory medicine specialists
• Regulatory authorities and conformity assessment bodies
• Metrology institutes involved in clinical measurement traceability

Related standards

• ISO 17511:2020 - Establishing metrological traceability for calibrators, trueness controls and human samples (referenced; ISO 21151 addresses case 5.6 of ISO 17511)
• ISO 11074 (terminology reference for aliquot)