“Trace” Benzoylecgonine Identifications in Post- Race Urines: Probable Sources and Regulatory Significance of Such Identifications

Cocaine is an environmental contaminant in North America. Benzoylecgonine (BZE) is the major urinary metabolite of cocaine in horses and humans, and urinary detection of BZE is highly sensitive. Human workplace drug testing typically uses a confirmatory “cutoff” for BZE of 150 ng/ml in urine. A number of horse-racing jurisdictions have adopted similar urinary “cutoffs” for BZE; this communication presents the scientific basis for these cutoffs and lists jurisdictions with urinary cutoffs for BZE. Authors’ addresses: Maxwell Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546 (Camargo, Hughes, Tobin); UK Livestock Disease Diagnostic Center, Lexington, KY 40511 (Lehner); and Florida’s Horsemen’s Benevolent and Protective Association, Opa Locka, FL 33056 (Stirling); e-mail: [email protected] (Camargo). © 2006 AAEP.