Section 285.8 - Proficiency testing(a)Proficiency testing requirements. Proficiency testing undertaken to meet the criteria for NVLAP accreditation shall be consistent with the provisions contained in NIST Handbook 150, NVLAP Procedures and General Requirements (incorporated by reference, see § 285.16 ), where applicable, including revisions from time to time. Laboratories must participate in proficiency testing as specified for each LAP in the NVLAP program handbooks.(b)Analysis and reporting. Proficiency testing results are analyzed by NVLAP and results of the analysis are made known to the participants. Any result not meeting the criteria specified in the NVLAP LAP program handbook is identified as a nonconformity.(c)Proficiency testing nonconformities.(1) Unsatisfactory participation in any proficiency testing program is a technical nonconformity which must be resolved in order to obtain initial accreditation or maintain accreditation.(2) Proficiency testing nonconformities are defined as, but not limited to, one or more of the following:(i) Failure to meet specified proficiency testing performance requirements prescribed by NVLAP;(ii) Failure to participate in a regularly scheduled "round" of proficiency testing for which the laboratory has received instructions and/or materials;(iii) Failure to submit laboratory control data as required; or(iv) 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.(3) NVLAP will notify the laboratory of proficiency testing nonconformities and actions to be taken to resolve the nonconformities. Denial or suspension of accreditation will result from failure to resolve nonconformities. 85 FR 60060 , Sept. 24, 2020