Antibodies for the blood-doping agent erythropoietin (EPO) have been detected in 12 horses in Louisiana over the past month, the state's racing laboratory confirmed on Monday.Dr. Steve Barker, director of the laboratory, told Daily Racing Form the trainers of the horses that tested positive have not been identified and no disciplinary action is likely to be taken because of concerns over the accuracy of the tests. "We're going to use the results to come up with a list of the trainers and veterinarians who may be using the drug and then use that for any follow-up investigations," Barker said. "If we start to get multiple hits on the same trainer, and there is a certain veterinarian associated with him, then we can have some confidence in coming up with a degree of positive cause."EPO is listed as a Class 2 substance under the guidelines of the Association of Racing Commissioners International and is banned in nearly every racing jurisdiction in North America. Class 2 drugs are identified by the ARCI as "drugs that have a high potential to affect performance...not generally accepted as therapeutic agents." A test to detect EPO, which was first used by track and field athletes and cyclists, was developed for horses late last year by scientists in New York and New Jersey.EPO antibodies have also recently been found in horses in Texas and New York.