Traceability of Testing Laboratory Measurements

Oral Presentation

Prepared by C. Kircher
Florida Department of Health, 1217 N. Pearl Street, Jacksonville, FL , 32202, United States

Contact Information: [email protected]; 904-791-1574


The NELAC Standards and ISO/IEC 17025 require laboratories to calibrate their equipment and make measurements that are traceable to the International System of Units (SI). If traceability to SI is not possible or relevant, the confidence in the testing laboratory measurements is enabled by establishing traceability to certified reference materials, specified methods, and/or consensus standards. For equipment calibrations, if traceability to SI is not possible, relevant, or desired, then the testing laboratory needs to establish that the associated contribution to the total uncertainty of the test result due to the equipment calibration is small. The NELAC Standards and ISO/IEC 17011 require the accreditation body to provide information about suitable ways to obtain measurement traceability in relation to the laboratory’s scope of accreditation.

These fundamental concepts of calibration, measurement traceability, and test result uncertainty may be obscured by other pressures on the laboratory, such as costs, personnel knowledge and training, and available time. While these concerns may be valid, they should not compromise the data quality needed for the test results and conformance with any applicable client or regulatory requirements. Therefore, this presentation will refresh and reacquaint participants with the SI units applicable to chemical, biological, and radiochemical measurements and with the options available to establish traceability where needed. Comments on reference materials and certificates of analysis will also be provided.