The Laboratories Administration of the Maryland Department of Health shall perform the analyses on urine samples received from the Commission. The preliminary urinalysis screen shall be performed by enzyme immunoassay or thin layer chromatography to detect the presence of controlled dangerous substances. A urine sample which tests positive for the presence of controlled dangerous substances as defined in Regulation .01B(2) of this chapter shall be retested by a confirmatory test to confirm the presence of the controlled dangerous substance. The confirmatory test shall be made by gas chromatography/mass spectrometry.