Hair Follicle Drug Testing: What You Need to Know
This test detects acepromazine, a veterinary tranquilizer, in hair samples to identify long-term drug exposure or use.
{"Acepromazine is a sedative primarily used in veterinary medicine for horses and companion animals","Hair testing can detect drug use over weeks to months, unlike blood or urine tests which only show recent use","This test is commonly used in equine sports and racing to check for illegal drug administration","Results help veterinarians and regulatory bodies ensure animal welfare and fair competition","The test analyzes hair strands for trace amounts of the drug deposited during growth"}
Key facts at a glance
- LOINC
- 78776-2
- Short code
- ACE-HAIR
- Synonyms
- Acepromazine Hair-mCnt
- Category
- chemistry
- Sample
- serum
- Container
- Sterile paper envelope or polypropylene container; do not use plastic bags
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
- CPT
- 80307
- SNOMED
- 785871009
- Specimen volume
- Minimum 100 mg of hair (approximately 100-200 strands); 1 cm segment preferred for segmental analysis
- Stability
- Room temperature stable for extended periods; store at room temperature away from direct sunlight and humidity
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 72–168 hours
- Order
- routine
What is hair testing and what can this test tell my healthcare provider about substance use over time?
The Acepromazine in Hair test is a laboratory analysis that detects the presence of acepromazine, a phenothiazine-class tranquilizer, in hair samples. Acepromazine is primarily used in veterinary medicine as a sedative, pre-anesthetic medication, and for controlling anxious or aggressive animals. While it is most commonly administered to horses, it may also be used in dogs, cats, and other animals.
How does hair testing work, and why can it detect drug use over a longer window than urine or blood testing?
When a person or animal is exposed to acepromazine, the drug circulates in the bloodstream and becomes incorporated into growing hair follicles. As hair grows, it traps trace amounts of substances, creating a permanent record of drug exposure. By analyzing a small sample of hair (typically collected from the scalp or other body area), laboratories can detect drug use that occurred weeks or months before the test. This makes hair testing particularly useful for detecting long-term or repeated drug use, rather than just recent exposure.
Why might my doctor order this test for me, such as for employment screening, treatment monitoring, or suspected substance use?
This test is most commonly ordered in veterinary and regulatory contexts, particularly in equine sports, racing, and show competitions. It helps ensure that animals have not been illegally administered performance-enhancing or calming drugs. Veterinarians may also order this test to monitor medication compliance, investigate unexplained behavioral changes in animals, or as part of a comprehensive toxicology screening. In rare human exposure cases, it may be used to determine if someone has been exposed to this veterinary medication.
Reference range
Negative or below detection limit (< 1 pg/mg); positive results indicate exposure to acepromazineN/A
Collect hair from the scalp vertex posterior region; hair should be cut as close to the scalp as possible; minimum 100 mg of hair (approximately 100-200 strands) required; avoid hair treatments that may contaminate sample; record hair color, length, and any chemical treatments
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The detection of acepromazine in hair has important clinical and regulatory implications. In veterinary medicine, unauthorized administration of acepromazine to performance animals can result in disqualification from competitions and legal consequences. The test helps enforce anti-doping regulations in equine athletics and ensures fair competition. For monitoring animal health, detecting acepromazine may explain unusual calmness or sedation that is otherwise unexplained. Additionally, hair testing can help identify cases of accidental overdose or inappropriate dosing in treated animals, allowing veterinarians to adjust treatment plans accordingly.
It is important to note that acepromazine is not approved for use in food-producing animals in many countries due to potential residue concerns. Hair testing may also be used in regulatory food safety programs to monitor for illegal drug use in livestock. The long detection window of hair testing (up to several months) makes it particularly valuable for investigations that occur well after potential drug administration.
Frequently asked questions
How is the hair sample collected?
How long can acepromazine be detected in hair?
Can hair testing determine exactly when the drug was used?
Is this test painful or invasive?
What can cause a false positive result?
Sources
- 1LOINC Code ReferenceSource
- 2
- 3
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy