ISO TS 20914-2019 PDF

Full title and description

ISO/TS 20914:2019 — Medical laboratories — Practical guidance for the estimation of measurement uncertainty. Provides practical, laboratory-focused guidance for estimating and expressing measurement uncertainty (MU) of quantitative measurand values produced by medical laboratories and for qualitative (nominal) methods that include a measurement step. It also addresses results produced near medical decision thresholds (including point‑of‑care testing) and recommends that MU estimates be made available on request rather than routinely attached to every patient result.

Abstract

This technical specification offers a pragmatic pathway for medical laboratories to calculate and express measurement uncertainty using laboratory-appropriate data and approaches. It aligns laboratory practice with international metrology principles while recognizing clinical context (e.g., decision limits and point‑of‑care testing) and includes examples (see Annex B) to illustrate application. The document emphasises availability of MU information on request rather than routine reporting with each patient result.

General information

• Status: Published (technical specification; reviewed/confirmed in ISO review cycle).
• Publication date: July 2019 (published July 2019; commonly cited publication date 29 July 2019 / July 2019).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 11.100.01 (Medical laboratory testing; laboratory medicine).
• Edition / version: Edition 1 (Technical specification, 2019).
• Number of pages: 73 pages (official ISO bibliographic entry).

Scope

Guidance for the estimation and expression of measurement uncertainty of quantitative measurand values produced by medical laboratories, including measurements near medical decision thresholds and point‑of‑care testing systems. The scope also explicitly covers estimating MU associated with results from qualitative (nominal) methods when those results include a measurement step. Routine reporting of MU with every patient result is not recommended; instead MU should be available on request and used for method validation, interpretation near clinical decision limits, and accreditation/performance assessment.

Key topics and requirements

• Practical procedures for constructing measurement uncertainty estimates appropriate to clinical laboratory workflows (use of internal quality control, external quality assessment and method validation data).
• Guidance for dealing with results close to medical decision thresholds and for point‑of‑care testing.
• Application to quantitative measurands and extension to qualitative methods that include measurement steps.
• Recommendations on expression of MU (absolute, relative or percentage), use of long‑term imprecision and combining uncertainty components relevant to laboratory practice.
• Worked example(s) in annex(es) (Annex B) to demonstrate practical application.
• Interaction with accreditation requirements and with ISO 15189 recommendations on uncertainty—supports laboratories in meeting accreditation and regulatory expectations.

Typical use and users

Clinical and medical laboratory managers, quality managers, clinical chemists, medical laboratory scientists, method validation teams, point‑of‑care testing programme leads, and accreditation bodies use this document to: develop laboratory-appropriate MU estimates, support method verification and validation, interpret results near clinical decision limits, and prepare evidence for accreditation assessments (ISO 15189/ISO 17025 contexts). Researchers and laboratory instrument manufacturers may also consult the specification when documenting performance characteristics or supporting laboratory customers.

Related standards

Key related standards and guidance documents include ISO 15189 (medical laboratories — quality and competence requirements), ISO/IEC 17025 (general laboratory competence and MU evaluation), and the Guide to the Expression of Uncertainty in Measurement (GUM / ISO/IEC Guide 98 series and JCGM publications). ISO/TS 20914 is intended to be used in conjunction with these documents when implementing MU practices in medical laboratories.

Keywords

Measurement uncertainty; MU; medical laboratories; clinical laboratory; point‑of‑care testing; decision thresholds; uncertainty estimation; GUM; ISO/TS 20914; ISO 15189; method validation.

FAQ

Q: What is this standard?

A: ISO/TS 20914:2019 is a technical specification from ISO that provides practical guidance for estimating and expressing the measurement uncertainty of results produced by medical laboratories. It is laboratory‑oriented and supplements general metrology guidance for the clinical testing context.

Q: What does it cover?

A: It covers practical methods to derive measurement uncertainty from laboratory data (internal QC, EQA, repeatability, calibration information), handling results near medical decision limits (including POCT), and approaches for qualitative methods that include measurement steps. It includes examples to illustrate application. Routine attachment of MU to every patient result is not recommended; MU should be available on request.

Q: Who typically uses it?

A: Clinical laboratory personnel (managers, quality officers, clinical scientists), accreditation assessors, method validation teams, and instrument/manufacturer specialists use this specification to implement MU estimation in medical testing and to support accreditation to ISO 15189 or equivalent schemes.

Q: Is it current or superseded?

A: ISO/TS 20914:2019 was published in 2019 and appears as the first edition technical specification; ISO standards and technical specifications are subject to periodic review (typically every five years). Users should check the ISO catalogue or national bodies for any subsequent revisions or confirmations (the document was reviewed in ISO’s periodic review process).

Q: Is it part of a series?

A: It is not a numbered multi‑part series, but it is part of the broader family of laboratory and measurement guidance used with standards such as ISO 15189 and ISO/IEC 17025 and with metrology guidance (GUM / ISO/IEC Guide 98 series). Laboratories commonly apply ISO/TS 20914 alongside these documents.

Q: What are the key keywords?

A: Measurement uncertainty, clinical laboratory, point‑of‑care testing, decision thresholds, uncertainty estimation, GUM, ISO 15189, method validation.