ACTH Stimulation Test

LABOKLIN Service ID: 141

Diagnosis

  • Initial diagnosis of Addison’s disease
  • Iatrogenic Cushing’s disease
  • Cushing’s disease
  • Horse: to clarify Addison’s disease /iatrogenic Cushing’s disease

Material

serum 2 x 0.5 ml

Execution

  • First blood collection = baseline value
  • Dog: injection of 5 μg ACTH/kg as Cosacthen® i.v./i.m.
  • Cat: injection of 5 μg/kg Cosacthen® i.v./i.m. (Addison’s disease only)
  • Guinea pig: baseline value cortisol, 20 IU ACTH/animal, 2. sample collection after 4 hours
  • Horse: injection of 100 IU ACTH i.v. (only hypoadrenocorticism)
  • Second blood collection 1 hour post ACTH injection = stimulation value in dogs and cats
  • Second blood collection 2 hours post ACTH administration = stimulation value in horses

Parameter

Cortisol

Method

CLA

Species list

dog, cat, horse, guinea pig, others on request

Duration

1 day

Assessment

  • 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 disease 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.
  • For the interpretation of therapy monitoring in Cushing's disease see 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. )
  • Guinea pig: for therapy monitoring of Cushing’s disease; at the time of diagnosis, it is not possible to differentiate between pituitary and adrenal Cushing’s disease; there are no reference values available.

Remark

An ACTH Stimulation Test can also be performed in guinea pigs from saliva (test number 1329 Salivary Cortisol Stimulation Test). This test is only run on request. Sample tubes are provided; saliva samples are analysed using ELISA detection method.