Adrenocorticotrophic hormone (ACTH) - plasma
10 mL blood in chilled EDTA tube; plasma separated and frozen immediately.
<50 ng/L (dependent on time of collection).
Investigation of the aetiology of corticosteroid excess or deficiency, as a baseline or as part of a suppression test (eg, dexamethasone, in conjunction with plasma and/or urine cortisol).
Corticosteroid excess may be associated with high ACTH levels (ectopic or pituitary source) or low levels (adrenal tumour).
Corticosteroid deficiency may be associated with high ACTH levels (primary adrenal insufficiency) or low levels (pituitary deficiency).
The Care Lab