International and Asian Screening Limits have the intention to ensure that racing jurisdiction screen therapeutic substances (veterinary drug substances which aid the recovery of the horse) to scientifically agreed sensitivities. Exceeding these concentrations, the substances are internationally verified to have therapeutic effect, and these must be controlled and prosecuted in the best interest and welfare of racing and the racehorse. 

The Asian Racing Federation (ARF) has recently approved and adopted the below Asian Screening Limit (ASL) for controlling Dexamethasone in plasma specimens (centrifuged blood) of the racehorse during racing:  ASL Dexamethasone in plasma at 0.02 ng/ml. 

The NHA has thoroughly researched this new ASL and it will soon be adopted within the NHA Laboratory screening of this particular prohibited substance. This new screening limit will be effective on specimens collected on and after Monday, 20 June 2022. 

During the last few years, the NHA studied the international research and administration trials which resulted in this limit been established and then adopted by the ARF. At the NHA Laboratory the screening of Dexamethasone in plasma is already (for several years) accurately aligned with this ASL. 

A urine International Screening Limit (ISL) for Dexamethasone (in racehorse urine on raceday) has been in place for many years at the NHA. The NHA has conducted literature research in order to confirm that the treatment detection and withdrawal periods which have been historically applied in this country in order to comply to this urine ISL will not result in racehorse plasma specimen concentrations exceeding this new plasma ASL. 

The implementation of this above ASL therefore does not require any change in the veterinary treatment of racehorses with this substance as it does not introduce more sensitive screening or prosecution of raceday specimens than previously in place at the NHA.