IF a trainer is using a drug too close to a race and gets a positive for it, it is considered only one positive test. IF NO ONE tells him he has a positive for that drug, and he continues to use the drug in such a fashion, he would accrue multiple positive tests. IF he is told he has a positive, one would be pretty foolish to continue to use that drug the same way. AND IT IS against the rules for racing commissions to do so. At least in every state I ever raced in.