If the chemical analysis of blood, urine, saliva, or other samples taken from a horse indicate the presence of a prohibited substance or NSAID or any metabolite or derivative thereof, it shall be prima facie evidence that the prohibited substance or NSAID has been administered to the horse. A hearing shall be held when a positive report is received from a chemist identifying a prohibited substance or any metabolite or derivative thereof, unless the requirements of Section 24011 have been met or the prohibited substance or NSAID consists solely of an exempt medication. The trainer or owner, or both the trainer and owner, responsible for the condition of the horse shall not be subject to the penalty prescribed under this chapter or suspended, and no horse shall be barred from competition until after the conclusion of the hearing and a written ruling thereon has been made by the secretary.