Page 112 - September 2016

Drug Screening TeSTS
new Options To check For Long-Acting Tranquilizers
tThe purpose of drug- testing is to create a level playing field, with no unfair advantage for any horse.
by Heather Smith Thomas
Drug screening is important to the rac- ing industry to make sure horses have no prohibited drugs in their system when
they race. The most common tests look for drugs that enhance performance and for anti-inflammatory medications (such as steroids and non-steroidal anti- inflammatory drugs) that might be used in a horse
to diminish pain and inflammation from a minor injury. The purpose of drug-testing is to create a level playing field, with no unfair advantage for any horse. Drug screening is important not only on race day, but also for sales and pre-purchase exams to make sure the horses being sold are not misrepresented. Sometimes, horses at sales have been given anti- inflammatory medication that might mask lameness, or a small dose of tranquilizer to aid in handling a nervous or flighty individual.
There are three primary types of drug-testing done at most laboratories. These three common
tests are thin-layer chromatography (TLC), enzyme- linked immunoassays (ELISA kits), and liquid or gas chromatography/mass spectronomy (LCMS/GCMS).
The TLC was the testing method of choice during the 1970s and 1980s because of its speed
and cost efficiency. It is still a quick way of testing a sample, but is relatively insensitive. It may only detect substances that were administered to a horse within the last few days.
The ELISA test kits became popular in the 1990s. Even though they are more expensive, they are also more sensitive. One test kit, which costs between
$50 and $100, can test between 80 and 86 samples
at once. Each kit can test for only one, or perhaps two or three closely-related drugs, however, making it expensive to test for a wide range of possible
drugs. A larger downside is the limitations of these ELISA tests—there aren’t kits available for all known substances that could be found in racehorses.
The LCMS/GCMS test is a more recent development in drug testing and has the advantage of being both highly sensitive and efficient, analyzing a sample to check for a vast number of known drugs in a single test. It is also the most expensive option for laboratories to develop and for customers to use. The LCMS/GCMS (also called instrumentation testing) is best, however, at keeping up with an evolving abundance of performance-enhancing drugs, many of which are easily tweaked to evade detection.
The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) recently developed a new screening test for long-acting tranquilizers. This test can be used in conjunction with other drug tests or by
itself, according to Travis Mays (Section Head), who oversees the Analytical Chemistry Section at TVMDL.
“The long-acting tranquilizer panel that we recently added stems from an equine pre-purchase drug screen that we began offering just over a year ago. That particular drug screen includes more than 30 non-steroidal anti-inflammatory drugs (NSAIDs) as well as three tranquilizers that are considered long-acting in veterinary medicine—at least in equine use. These include fluphenazine, fluoxetine, and reserpine. The pre-purchase drug screen encompasses all of these drugs, but we felt it would be beneficial to give veterinarians the ability to test just for the tranquilizers in situations where
Travis Mays, who grew up riding on his family’s ranch and working at his father’s mixed-animal veterinary hospital, oversees the Analytical Chemistry Section at the Texas A&M Veterinary Medical Diagnostic Laboratory.
110 SPEEDHORSE, September 2016
equine health