SIR #: 75
Standard: 2003 NELAC
Section: 2.2.1, Appendix C.3
Link to relevant standard
The result for EDB of <0.500ug/L was scored "not acceptable", against the true value of 0.299ug/L and limits of 0.179-0.419ug/L. This result is not identified as consideration for unacceptable criteria.
We disagree, and feel that this result should be scored acceptable. 0.299ug/L is less than 0.500ug/L.
TNI FINAL RESPONSE:
(PT Executive Committee/NELAP Accreditation Council, x-x-10)
Based upon current acceptance criteria, the lab result for the analyte provided in the problem statement was correctly scored as not acceptable. Acceptance criteria for this analyte are currently based on the PT acceptance requirements outlined in Chapter 2 and Appendix C of the 2003 NELAC Standard.
In addition, the FoPT tables currently include a footnote that states, "NELAC Proficiency Testing Reporting Limits (PTRLs) are provided as guidance to laboratories analyzing NELAC PT samples. These levels are the lowest acceptable results that could be obtained from the lowest spike level for each analyte. The laboratory should report any positive result down to the PTRL. It is recognized that in some cases (especially for analytes that typically exhibit low recover) that PTRL may be below the standard laboratory reporting limit. However, the laboratory should use a method that is sensitive enough to generate results at the PTRL shown..."
The laboratory should be aware of and take into account the corresponding PTRL for each analyte before reporting any PT results.