Understanding and Managing Proficiency Testing Requirements for Laboratory Accreditations

Best Management Practices for Environmental Laboratories
Oral Presentation

Prepared by C. Valkenburg
Perry Johnson Laboratory Accreditation Inc., 755 W. Big Beaver Rd. Suite 1325, Troy, Michigan, 48084, United States

Contact Information: [email protected]; 1-248-519-2603


Analysis of Proficiency Testing (PT) Samples is required for the certification and accreditation of Environmental Analytical Testing Laboratories under a complex array of Federal, Government Agency, and State regulatory programs and regulations. TNI (The NELAC Institute) provides a list of approved PT providers, and details PT requirements and specifications for Proficiency testing within their accrediting standards. TNI Fields of Proficiency Testing (FOPT) Tables, and TNI Method and Analyte Code Tables, are utilized nationally for PT analysis, PT reporting, and PT scoring. Individual states, and other accreditation programs such as DOD/DOE ELAP may also have additional PT analysis requirements. TNI approved Non-Governmental Accrediting Bodies (NGABs) have established Proficiency Testing analysis policies for accreditation of calibration and testing laboratories under ISO/IEC 17025:2017 standards and which can be useful guidance to meet Proficiency Testing Requirements when commercially prepared PT samples are not available.

The presentation discusses why the analysis of PT samples is important to evaluation of method performance, how state and agency program requirements may vary, and the effectiveness that PT samples can have in the overall evaluation of Laboratory Quality Systems. Also included in the discussion, critical to successful PT analysis is: PT ordering and scheduling of PT’s of appropriate design; selection of matrix/methods/analytes to be reported; generalized PT provider reporting requirements; PT receipt handling, storage, and preparation issues; PT analysis guidance and possible concerns; needed PT reporting details; the evaluation of PT scoring results; examples of PT Corrective Actions and the various Root Causes possible/common for not-acceptable PT results; PT make-up study management; and the importance of a PT results tracking system for the overall management of PT results related to accreditations.