The Racing Medication and Testing Consortium (RMTC) executive committee has approved a uniform testing threshold of 110 parts per billion (ppb) in blood for the naturally occurring amino acid gamma-aminobutyric acid (GABA).

The threshold, which was developed by the RMTC’s Scientific Advisory Committee (SAC), will be submitted today (April 15) to the Association of Racing Commissioners International (RCI) for consideration as a model rule at RCI’s meeting next week in Tampa Bay, Florida. The SAC is a standing committee of the RMTC, comprised of leading chemists, pharmacologists, lab directors, regulatory veterinarians, and racetrack veterinarians from across the U.S. horse racing industry.

The RMTC has already submitted a recommended testing threshold for cobalt, another naturally occurring substance in horses.

“This proposal is designed to protect the health and welfare of the race horse,” explained Scott Hay, DVM, RMTC SAC co-chair. “It is always challenging to determine thresholds on substances that are both endogenous and can be used inappropriately in an attempt to influence the outcome of a race. The RMTC SAC spent a significant amount of time to make sure that illegal race day administrations of GABA would be controlled without risking inadvertent positive tests of a substance that is naturally present in a horses system.”

Believed to have a calming effect on horses for up to three to four hours, GABA has been inappropriately administered on race-day as a performance enhancer through a supplement called C