BHA maintains a policy of strict liability for the presence of any drug, including medications, on racedays. Screening Limits are instructions to laboratories which set a level above which medications are reported, in recognition that minuscule amount of medication have no effect.

Quantification of the amount of medication present in a positive sample is not necessary because there is no regulatory threshold for medications; the Screening Limit is a policy decision that recognises the analytical sensitivity of modern laboratory technology. It is more expensive to carry out quantitative analysis done therefore it doesn’t represent best value for the sport’s participants.