The TNI Fields of Proficiency Testing Change Process

Operational and Advocacy Issues Impacting the Environmental Laboratory Industry
Oral Presentation

Prepared by M. Friedman
State Water Resources Control Board, 500 N Central Ave, Suite 500, Glendale, CA, 91203, United States

Contact Information: [email protected]; 818-551-2014


Among the pillars of the TNI Proficiency Testing Program are the Fields of Proficiency Testing (FoPT) Tables - that specify the matrices, analytes, concentration ranges, and acceptance limits that are used to evaluate the performance of accredited laboratories. The TNI Proficiency Testing Program Executive Committee (PTPEC) is responsible for maintaining the FoPT Tables, and evaluates historical PT sample data periodically to ensure that the FoPTs continue to challenge the critical components of each analytical procedure. However, a limitation of the FoPT evaluation process is that the statistical approach used to calculate acceptance limits addresses interlab variability while ignoring the minimum inherent variability of different methods. Suppose you work for a lab that wants to be accredited for an FoPT, but find that the acceptance criteria seem inappropriate for the method you are running? What recourse do you have?

Matters involving FoPTs can have wide-ranging effects for the PT Providers, Accreditation Bodies, and thousands of laboratories across the country that participate in PT studies each year. Accordingly, no changes are taken lightly, and great care is taken to ensure that changes do not cause adverse unintended consequences. The PTPEC has a process whereby any PT Program participant may petition to change, add, or remove FoPTs. This process uses a petition format called the Analyte Request Application, or ARA.

In this presentation, the Chair of the PTPEC will review the ARA process, using the recent experience of an ARA that proposed a major change in how Coliform FoPTs are reported. You will learn about how the PTPEC handles ARAs, collects PT data and enlists experts to ensure that the proper and responsible due diligence is exercised in the evaluation of all such requests.