Erythropoietin, a human medication designed to increase the concentration of red blood cells that is rumored to be in use on racehorses, has been added to the list of prohibited veterinary substances on racing premises by the California Horse Racing Board.

The board voted unanimously at its Wednesday meeting to take the action, adding California to a growing list of states taking similar action including Kentucky, New York, New Jersey, and Maryland.

Dr. Ronald Jensen, CHRB equine medical director, recommended the addition of Erythropoietin, known as EPO, and its closely related medication, Darbepoietin, to the list of banned substances although a test has not been developed yet for accurate detection of the drugs.

“There are substances that may be in use at racetracks that are difficult to detect under current laboratory testing methods,” he said. Jensen said that officials continued to work on finding a successful method for testing with current technology