ACTH, plasma
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 ...
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).
Test Details
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Discipline:
Biochemistry
Biochemistry
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Specimen Container Adult:
EDTA plasma
EDTA plasma
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Specimen Container Paediatric:
EDTA plasma
EDTA plasma
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Minimum Volume Adult:
1 mL
1 mL
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Minimum Volume Paediatric:
1 mL
1 mL
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Sample Stability:
Unseparated sample: 6 hours
Separated sample: 6 weeks at -20oC
Unseparated sample: 6 hours
Separated sample: 6 weeks at -20oC
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Transport Requirements:
Frozen
Frozen
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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 in...
Read MoreIn 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.
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Reference Ranges:
7.2 to 63.3 ng/L (sample taken between 7 and 10 am)
7.2 to 63.3 ng/L (sample taken between 7 and 10 am)
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Routine Contact Name:
Duty Biochemist
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Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719
Freeman: 0191 244 8889
RVI: 0191 282 9719
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Routine Email:
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Specialist Test:
Yes
Yes
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Specialist Contact Name:
Endocrine Lab
Endocrine Lab
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Specialist Telephone:
0191 282 4025
0191 282 4025