The stewards or judges may designate a horse entered in a race to give a blood or urine sample, or both, before or following the race. At the conclusion of each race, urine and blood samples shall be collected from the winner of the race and any other horses that the Commission or stewards or judges may direct. The collection of the urine sample shall be performed by a Commission representative in the presence of the owner, trainer, or designated representative of the horse being tested. An authorized official designated by the Commission, in the presence of the owner, trainer, or designated representative and the Commission representative, shall verify the horse's identifying tattoo or microchip number before taking a blood sample from the horse. Failure to allow or cooperate in the taking of a sample, or any act or threat to impede, prevent, or otherwise interfere with the taking of a sample, constitutes a violation and subjects the licensee to sanctions as provided in this chapter. Urine. Except as provided in §F(2) of this regulation, after the Commission representative obtains the urine specimen from the horse, the Commission representative or the detention barn foreman shall split the specimen into two parts in the presence of the owner, trainer, or designated representative. One portion shall be delivered to the Commission laboratory for testing. The remaining portion shall be maintained in the detention barn until the stewards or judges direct its disposal. If the quantity of the urine specimen collected is insufficient to allow for proper testing, the specimen may not be split. Blood. After the horse has been washed down, an authorized official designated by the Commission shall extract two tubes of blood from the horse. Of the two tubes of blood drawn under §G(1) of this regulation, one shall be forwarded to the Commission laboratory for testing. The remaining tube of blood shall be maintained at the detention barn until the stewards or judges direct its disposal. If necessitated by an insufficient quantity of urine having been obtained, another tube of blood shall be drawn and forwarded to the laboratory. Split Samples. The Commission, together with the applicable association representing a majority of the owners and trainers racing in Maryland, shall designate laboratories to which split samples of urine and blood may be sent for confirmatory testing. Within 72 hours of being notified of a determination by the Commission laboratory that the testing of the blood or urine sample evidences the presence of a drug, the owner or trainer of the horse in question may request that the split sample of urine or blood, or both, be forwarded to one of the designated laboratories for confirmatory testing. Upon a request for confirmatory testing, before the split sample is forwarded to the designated laboratory, the owner or trainer and a representative of the Commission shall execute an agreement that binds the owner or trainer and the Commission to the designated laboratory's findings. If the owner or trainer declines to execute the agreement, the split sample may not be forwarded to the designated laboratory for confirmatory testing. After testing the split sample, if the designated laboratory: Does not confirm substantially the Commission laboratory's findings, then any allegations that the drug in question was in the horse's system at the time of the race shall be dismissed; or Confirms substantially the Commission laboratory's findings, then the finding shall be considered conclusive. If, for whatever reason, confirmatory testing is not possible, §H(1)—(4) of this regulation is of no effect. The owner or trainer requesting the confirmatory testing shall bear the costs of the confirmatory testing.