Laboratory testing of proficiency test study samples

To ensure valid proficiency test results, the laboratory shall: 1. Obtain all proficiency test study samples as unknowns from a nationally recognized accreditation program approved vendor; 2. Manage, analyze, report, and otherwise handle all proficiency test samples in the same manner as routine samples, including the same staff, procedures, equipment, and facilities used for routine analysis for the field of testing; 3. Employ the same calibration, quality control, acceptance criteria, sequence of analytical steps, number of replicates, and other standard operating procedures for proficiency test samples as used when analyzing routine samples; and 4. Follow sample preparation steps for the proficiency test sample as instructed by the proficiency test sample provider.