Equis ISSN 2398-2977
Endocrine: ACTH stimulation test for PPID
Synonym(s): Adrenocorticotrophic hormone stimulation test
Contributor(s): Kathleen P Freeman, Ramiro Toribio, Han van der Kolk, David Rendle
Overview
- Dynamic response of adrenal gland to ACTH stimulation.
- Reported to result in an exaggerated response in 75% of horses with pituitary pars intermedia dysfunction (PPID) Pituitary pars intermedia dysfunction (PPID), yet only around 20% of horses with PPID will have adrenal pathology.
- Overlap of values with normal horses.
- Not considered reliable and no longer used in the diagnosis of PPID.
- Measures cortisol concentration.
Sampling
This article is available in full to registered subscribers
Sign up now to purchase a 30 day trial, or
Login
Tests
Methodologies
- Radioimmunoassay.
- Chemiluminescence.
- Method determines required specimen type (plasma or serum).
Availability
- Most veterinary commercial, reference or university laboratories.
Validity
Sensitivity
- Check with laboratory to determine that their method has been validated for horses and that reference interval/guidelines for interpretation are available.
- Estimated sensitivity of 75-80 %.
- Some overlap with responses obtained in normal horses.
Specificity
Technique (intrinsic) limitations
- Some overlap of values with responses obtained in normal horses.
- Resting cortisol (pre-ACTH) may be low, within normal limits or elevated.
- Both false negative and false positive tests may occur.
Technician (extrinsic) limitations
- Requires interpretation in conjunction with clinical signs and results of other testing.
Result Data
This article is available in full to registered subscribers
Sign up now to purchase a 30 day trial, or
Login
Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Couetil L et al (1996) Plasma adrenocorticotropin concentration in healthy horses and in horses with clinical signs of hyperadrenocorticism. J Vet Intern Med 10 (1), 1-6 PubMed.
- Van der Kolk J H et al (1995) Laboratory diagnosis of equine pituitary pars intermedia adenoma. Domestic Animal Endocrinol 12 (1), 35-39 PubMed.
- Sojka J E et al (1995) Evaluation of endocrine function. Vet Clin North Am Equine Pract 11 (1), 415-435 PubMed.
- Dybal N O et al (1994) Diagnostic testing for pituitary pars intermedia dysfunction in horses. JAVMA 204, 627-632 PubMed.
- Beech J et al (1987) Evaluation of thyroid, adrenal and pituitary function. Vet Clin North Am Equine Pract 3, 649-661 PubMed.
Other sources of information
- Reed S M (2004) Pituitary Adenomas; Equine Cushing's Disease. In: Equine Internal Medicine. 2nd edn. Eds: Eds: Reed S M, Bayly W M & Sellon D C. Philadelphia: W B Saunders Co. pp 1327-1330. ISBN-10: 0721697771; ISBN-13: 978-0721697772.
- Smith B P (2001) Endocrine Disorders. In: Large Animal Internal Medicine. 3rd edn. Mosby, St Louis. pp 1223-1236. ISBN-10: 0323009468; ISBN-13: 978-0323009461.