Stock show season brings together months of preparation for exhibitors and their animals. Veterinarians play a key role in ensuring that performance animals are managed responsibly and in compliance with competition rules.
The Texas A&M Veterinary Medical Diagnostic Laboratory, TVMDL, offers performance animal drug screening using modern LC/MS (liquid chromatography–tandem mass spectrometry). Each year, TVMDL performs thousands of these tests for hundreds of clients. The efficiency of LC/MS allows multiple compounds and cases to be analyzed without compromising accuracy or reliability, helping veterinarians protect animals and preserve fairness in shows.
In this article
- The role of LC/MS
- What is detected?
- Step by step: How the test is performed
- Interpreting results: Considerations for veterinarians
- Turnaround time
- Key takeaways
The role of LC/MS
LC/MS has become the gold standard for performance animal drug screening due to its sensitivity, specificity, and flexibility. At a high level, this technology combines two powerful analytical techniques: liquid chromatography (LC), which is a lab technique that separates compounds within a sample, and mass spectrometry (MS), which detects and identifies those compounds based on their molecular characteristics.
Together, LC/MS allows TVMDL to detect drugs at extremely low concentrations while still confidently distinguishing between different substances.
Key advantages of LC/MS for veterinarians include:
- Detection of both parent drugs and metabolites
- Ability to identify substances long after clinical effects have resolved
- Broad screening capability in a single analytical run
What is detected?
TVMDL’s LC/MS drug screening options are intentionally broad in scope, covering more than 100 compounds that may affect performance, appearance, or behavior.
These include, but are not limited to:
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Sedatives and tranquilizers
- Corticosteroids
- Opioids
- Bronchodilators
- Diuretics
- Anabolic and performance-enhancing agents
A broad screening approach is critical to detect the continually evolving range of drugs and formulations. Importantly, detection does not automatically imply wrongdoing. Animals may receive appropriate veterinary treatment yet still have detectable residues due to the high sensitivity of these testing methods. TVMDL’s animal drug screening is designed to capture this information so it can be interpreted in context.
Step by step: How the test is performed
Understanding the testing process can help veterinarians explain results to clients and reinforce confidence in the laboratory’s findings.
1. Specimen/sample intake and case review
- The blood, urine or other sample types are received by TVMDL
- Sample labeling and documentation are verified
- Each case is assigned a unique identifier
2. Sample preparation (extraction)
Before analysis, samples undergo a carefully designed extraction process:
- Solid-phase extraction is used to isolate drugs and metabolites
- Interfering substances are removed
- Chemical properties such as pH, polarity, and lipophilicity are considered to capture the highest possible amount of each substance
3. LC/MS analysis
- Liquid chromatography separates compounds within the sample
- Mass spectrometry identifies each compound with high specificity
- Detection limits reach extremely low concentrations (levels as low as one part per billion)
4. Quality control and confirmation
To protect the integrity of results:
- Internal standards and controls are used with every run
- Positive screens are confirmed using:
- Re-extraction of the original sample
- Additional analytical runs
- Matching retention times and fragment ion patterns
- Confirmatory testing on a separate instrument for added accuracy
This multi-step approach upholds accuracy and reliability, giving confidence in the results before they are reported.
Interpreting results: Considerations for veterinarians
Animal drug screening results generally fall into one of three categories:
- Non-detected
- Detected below an established threshold
- Detected above an established threshold
It is important to note:
- Thresholds are set by individual stock shows or governing bodies
- In the absence of thresholds, all detected substances are reported
- Estimated concentrations are provided to support interpretation
TVMDL works closely with veterinarians and show officials to help clarify results, discuss thresholds, and answer questions. Early communication between veterinarians and clients regarding drug use and withdrawal times remains one of the most effective ways to reduce unintended detections.
Turnaround time
TVMDL publishes a standard turnaround time of 14 business days for performance animal drug screenings. In many cases, results may be available sooner depending on caseload and the need for confirmatory testing.
Key takeaways
For veterinarians working with performance animals, early planning, open communication, and informed use of diagnostic testing are key to achieving the best outcomes for clients and animals alike.
For more information about animal drug screening or TVMDL’s testing options, visit tvmdl.tamu.edu or call the College Station laboratory at 888-646-5623.