An increase in requests for testing of split samples taken from horses competing in North America–attributable in part to the legalization of clenbuterol–is adding to the workload at drug-testing labs around the country.

Dr. Rick Sams, director of the Analytical Toxicology Laboratory at Ohio State University, said personnel constraints imposed by split-sample testing led to the decision by the institution to no longer perform such tests.

Under rules in most North American racing jurisdictions, connections of horses that test positive in post-race analysis can request to have a portion of the sample sent to an independent laboratory for additional testing. The split-sample tests performed by the second, or “reference,” lab are usually more in-depth than the initial testing that led to the positive finding. Most racing commissions maintain lists of approved labs.

In a letter to Roy Wood Jr., executive director of the California Horse Racing Board, Sams said OSU will not accept referee samples from any racing jurisdiction. “I made this decision after careful review of the impact of the demands of referee sample testing upon our laboratory operations,” Sams said. “I determined that it was necessary to cease referee sample testing so the laboratory could meet its contractual obligations to the Ohio State Racing Commission and the Ohio Department of Agriculture in a more timely manner