Endogenous adrenocorticotropic hormone (ACTH) – Equine
The Endogenous Adrenocorticotropic Hormone (ACTH) test is a diagnostic tool used to measure ACTH levels in equine plasma, aiding in the diagnosis of equine pituitary pars intermedia dysfunction (PPID), commonly known as Cushing’s disease. ACTH, a hormone produced by the pituitary gland, regulates cortisol secretion from the adrenal glands. In horses with PPID, abnormal pituitary function leads to excessive ACTH production, resulting in chronic hypercortisolemia and associated clinical signs.Horses with PPID often exhibit symptoms such as a long, curly hair coat (hirsutism), weight loss, muscle wasting, laminitis, increased thirst and urination, and susceptibility to infections. Measuring endogenous ACTH is particularly valuable during the autumn seasonal rise when ACTH levels naturally fluctuate, as affected horses show disproportionately high increases compared to healthy individuals. This test is minimally invasive and, when interpreted alongside clinical signs, provides veterinarians with critical information for diagnosing and managing PPID effectively.
Test name
Endogenous adrenocorticotropic hormone (ACTH) – Equine
Test Code
E119
Section
Endocrinology
Species
Equine
Specimen
2 ml EDTA Plasma
Collection Guidelines
- Collect blood using an appropriate EDTA (Purple-Top) vacutainer tube.
- Centrifuge the sample to separate the plasma. Transfer the clear plasma into a new, leak-proof plain EDTA tube and label it as “Plasma.”
- Avoid using excessively hemolyzed samples, as they are unsuitable for this test.
- Unspun samples will not be accepted.
- Refrigerate the sample at 4°C until shipment.
Turnaround time
14-21 days
Packing Instructions
Label each sample with the animal’s name and a unique identifier, using a permanent marker or a secure adhesive label. Ensure the submittal form is completed with the animal’s information and relevant medical history.
References
- McFarlane, D., et al. “Advances in the Diagnosis and Management of Equine Cushing’s Disease.” Journal of Veterinary Internal Medicine, 2021.
- Beech, J., et al. “Seasonal Variations in ACTH Levels and Implications for PPID Diagnosis.” Veterinary Clinics of North America: Equine Practice, 2022.
- Durham, A.E., et al. “Utility of Endogenous ACTH Measurement in Diagnosing and Managing PPID in Horses.” Journal of Veterinary Diagnostic Investigation, 2023.
