(a) Each laboratory shall have its own internal quality control program and shall analyze a suitable control sample with each set of 50 samples.

(b) Each laboratory shall demonstrate acceptable performance in an external proficiency testing program. The Department shall submit blind proficiency test samples on a random basis to each methadone program director; at least 12 samples per quarter shall be submitted. The methadone program director shall, in turn, submit this sample to the methadone drug analysis laboratory in a container which is normally used by the program. Each container shall bear identifying numbers and letters that are indistinguishable from those used by patients in that program. The proficiency test samples shall arrive at the laboratory intermingled with other regular specimens. When the analysis is completed, the methadone program director shall forward the results of the analysis to the Department. The Department shall notify both the methadone program director and the director of the methadone drug analysis laboratory of the results of the proficiency test at the end of each month.