Feb 17, 2019 Last Updated 9:07 PM, Feb 8, 2019

Measurement Uncertainty Requirements for Laboratories


Uncertainty of measurement is defined as a “parameter, associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand” (the measurand is the particular quantity subject to measurement) (International Vocabulary of Metrology, 2008).

There is growing recognition of the importance of Measurement Uncertainty (MU) and traceability to assuring the reliability of measurement. This is reflected in the standard ISO/IEC 17025:2005 and ISO 15189:2012, which contain enhanced requirements concerning these issues. The reactions to these developments range from interpretation at a minimal level, to implementation in a full and costly manner. Uncertainty of measurement is best estimated within the individual laboratory environment. All factors which will have a significant influence on the test or measurement result must be included in the estimated process. There must be suitable programs utilizing reference standards, instruments and materials to ensure on-going and adequate quality control and repeatability and reproducibility of methods and equipment over time. In many instances, it will be possible to utilize quality control data in assessing uncertainty components such as precision. Where these data are not available, it may be necessary to carry out precision studies or to rely on published information about the method or portions of it until the laboratory can obtain its own estimates. The ILAC-G17:2002 should be used as a guidance document as well to supplement the content of this document.

Notice of Transition to
ISO/IEC 17011:2017

    JANAAC is currently in transition to the new ISO/IEC 17011:2017 standard. As such, all our accredited CABs and new applications will be informed in a timely manner of any accreditation requirements which may be affected. Please contact JANAAC for further information or clarifications.

    Notice of Transition to
    ISO/IEC 17025:2017

    ILAC, in consultation with ISO, has agreed on a three-year period for laboratories that demonstrate conformity to the ISO/IEC 17025 standard, to make the transition from ISO/IEC 17025:2005, to the ISO/IEC 17025:2017 version of the standard. A communique has been issued in this regard. JANAAC, in keeping with this communique, requires its accredited laboratories to make this transition by November 30, 2020. After this date, accreditation to ISO/IEC 17025:2005 will no longer be valid. During this transition period, both revisions of the standard are equally valid and applicable. Testing and calibration laboratories may continue to submit applications for accreditation to the ISO/IEC 17025:2005 standard up to December 31, 2018, in which case, initial assessments must be conducted by March 31, 2019. After December 31, 2018, JANAAC will no longer be accepting applications for ISO/IEC 17025:2005 accreditation. After March 31, 2019, all assessments (initial, re-assessments and interim assessments, including scope extensions) will be conducted using the revised standard, ISO/IEC 17025:2017. If the date of reassessment or interim on-site assessment (surveillance) occurs before Nov 30, 2020, and after December 31, 2018 the laboratory will be assessed against the ISO/IEC 17025:2017 standard, in accordance with international practice. All accredited and applicant testing and calibration laboratories are required to purchase a copy of the revised standard at the earliest opportunity and to commence the transition process. Please contact JANAAC for any further information and clarification required.