NVLAP proficiency testing is consistent with the provisions contained in ISO/IEC Guide 43 (Parts 1 and 2), Proficiency testing by interlaboratory comparisons, where applicable, including revisions from time to time. Proficiency testing may be organized by NVLAP itself or a NVLAP-approved provider of services. Laboratories must participate in proficiency testing as specified for each LAP in the NVLAP program handbooks.

Analysis and reporting. Proficiency testing data are analyzed by NVLAP and reports of the results are made known to the participants. Summary results are available upon request to other interested parties; e.g., professional societies and standards writing bodies. The identity and performance of individual laboratories are kept confidential.

Proficiency testing deficiencies. (1) Unsatisfactory participation in any NVLAP proficiency testing program is a technical deficiency which must be resolved in order to obtain initial accreditation or maintain accreditation.

Proficiency testing deficiencies are defined as, but not limited to, one or more of the following:

Failure to meet specified proficiency testing performance requirements prescribed by NVLAP;

Failure to participate in a regularly scheduled “round” of proficiency testing for which the laboratory has received instructions and/or materials;

Failure to submit laboratory control data as required; and

Failure to produce acceptable test or calibration results when using NIST Standard Reference Materials or special artifacts whose properties are well-characterized and known to NIST/NVLAP.

NVLAP will notify the laboratory of proficiency testing deficiencies and actions to be taken to resolve the deficiencies. Denial or suspension of accreditation will result from failure to resolve deficiencies.