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Standard Interpretation

Standard: 2003 NELAC
Section: Appendix C.1 (a), C.3.1, C.3.2


A laboratory in our program has requested clarification that the term "outside source" has the same or a different meaning from the term "secondary source." The laboratory understands that a "secondary source" should be used for instrument calibration per NELAC but this is not required for demonstration of capability or determination of LOD or determination of LOQ. The question is "Is 'outside source' the same as 'secondary source'?" Thank you for your assistance.


The term outside source is not equivalent to the term secondary source.

The outside source cited in C.1 a) meant a source other than calibration standards. This is consistent with the definition of Quality Control Sample, which may be a Certified Reference Material, quality system matrix fortified by spiking, or actual samples fortified by spiking.