Dec 14, 2018 Last Updated 9:09 PM, Dec 13, 2018

Measurement Uncertainty Requirements for Laboratory


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 17025:2017

JANAAC, in keeping with an ISO/ILAC 17025:2017 transition communique, requires all testing and calibration laboratories to make the transition to the ISO/IEC 17025:2017 standard by November 2020. During this transition period, ISO/IEC 17025:2005 and ISO/IEC 17025:2017 are equally valid. Testing and calibration laboratories may continue to submit applications for accreditation to ISO/IEC 17025:2005 up to December 31, 2018. After December 31, 2018, however, JANAAC will no longer be accepting applications for ISO/IEC 17025:2005 accreditation. Re-assessment or surveillance visits, however, done after December 31, 2018 will be done using the new standard. Please contact JANAAC for further information or clarifications.

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.