Section 493.1236 - Standard: Evaluation of proficiency testing performance(a) The laboratory must review and evaluate the results obtained on proficiency testing performed as specified in subpart H of this part.(b) The laboratory must verify the accuracy of the following:(1) Any analyte or subspecialty without analytes listed in subpart I of this part that is not evaluated or scored by a CMS-approved proficiency testing program.(2) Any analyte, specialty or subspecialty assigned a proficiency testing score that does not reflect laboratory test performance (that is, when the proficiency testing program does not obtain the agreement required for scoring as specified in subpart I of this part, or the laboratory receives a zero score for nonparticipation, or late return of results).(c) At least twice annually, the laboratory must verify the accuracy of the following: (1) Any test or procedure it performs that is not included in subpart I of this part.(2) Any test or procedure listed in subpart I of this part for which compatible proficiency testing samples are not offered by a CMS-approved proficiency testing program.(d) All proficiency testing evaluation and verification activities must be documented.