ACTH StimulationTest

LABOKLIN Service ID: 141


  • Initial diagnosis of Addison’s disease
  • Iatrogenic Cushing’s disease
  • Cushing’s disease


Serum 2 x 0.5 ml


  • First blood collection = baseline value
  • Dog, ferret: injection of 5 μg ACTH/kg as Cosacthen® i.v./i.m.
  • Cat: injection of 5 μg/kg Cosacthen®/animal i.v./i.m.
  • Horse: injection of 100 I.U. ACTH i.v. (only hypoadrenocorticism)
  • Second blood collection 1 hour post ACTH injection = stimulation value in dogs and cats





Species list

Dog, cat, ferret, horse, others on request


1 day


  • Addison’s disease/iatrogenic Cushing’s disease: cortisol concentration post stimulation < 10 ng/ml (20 ng/ml in 8% of the cases, in central Addison’s a moderate stimulation > 20 ng/ml can be expected in dogs).
  • In Cushing’s disease (hyperadrenocorticism), the cortisol concentration post stimulation exceeds 150 ng/ml or is more than 3 times the baseline value, as long as it is in the middle of the normal range. Chronic stress and other underlying diseases (e.g. diabetes mellitus) can also lead to an abnormal ACTH response. According to the literature, a stimulation value > 220 ng/ml is, to a very high percentage, associated with Cushing’s disease.
  • It should be noted that approx. 15% of the dogs with pituitary and approx. 40% of the dogs with adrenal hyperadrenocorticism show a normal, i.e. not significantly elevated increase.
  • Therapy monitoring in Cushing’s disease by means of Vetoryl Therapy Control (see category Endocrinology)
  • Horse: In healthy animals, the cortisol level increases by approximately 80%; horses with hypoadrenocorticism show very low baseline values which do not or only slightly increase after stimulation.