Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Adrenocorticotropic hormone (ACTH), the primary stimulus for adrenal cortisol production, is synthesized by the pituitary in response to corticotropin-releasing hormone (CRH), which is released by the hypothalamus. Plasma ACTH and cortisol secretion displays a strong circadian variation with an early morning peak and late-night nadir.
Measurement of ACTH may be useful in the differential diagnosis of hypercortisolism (e.g. Cushing’s disease, ectopic ACTH production, adrenal cortisol producing tumours) and hypocortisolism (e.g. primary adrenal insufficiency, secondary adrenal insufficiency, congenital adrenal hyperplasia). ACTH may be measured on single (usually timed) specimens or as part of a dynamic function test such as the CRH test or inferior petrosal sinus sampling (IPSS).
Specimen container paediatric:
EDTA plasma
Specimen container adult:
EDTA plasma
Minimum volume paediatric:
1 mL
Minimum volume adult:
1 mL
Sample stability:
- Unseparated sample:
- 6 hours
- Separated sample:
- 6 weeks at -20oC
Transport requirements:
Frozen
Statement:
This test is not currently under the scope of UKAS accreditation but is fully quality assured.
Interpretation:
In hypocortisolism, an elevated adrenocorticotropic hormone (ACTH) suggests primary adrenal insufficiency, whereas a value that is not appropriately elevated is consistent with secondary adrenal insufficiency (pituitary/hypothalamic). In hypercortisolism (Cushing syndrome), a suppressed ACTH is consistent with a cortisol-producing adrenal adenoma or carcinoma, primary adrenal micronodular hyperplasia, or exogenous corticosteroid use. Normal or elevated ACTH in a patient with Cushing syndrome suggests ACTH-dependent Cushing syndrome. This can be due to an ACTH-producing pituitary adenoma or ectopic ACTH production. Further testing such as dexamethasone suppression, CRH stimulation testing, IPSS and imaging studies are usually necessary to determine the source of ACTH production.
Reference ranges:
7.2 to 63.3 ng/L (sample taken between 7 and 10 am)