ACTH

Clinical Chemistry

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Description

Adrenocorticotropic hormone (ACTH), is a hormone released from the anterior pituitary gland. It stimulates the release of cortisol from the adrenal glands. ACTH is measured with cortisol to assess the hypothalamic-pituitary-adrenal axis when adrenal insufficiency is suspected. ACTH is also used in the differential diagnosis of Cushing's syndrome. ACTH is only stable for a limited time so samples should be delivered to the laboratory promptly.

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Indications

1. Differential diagnosis of adrenal insufficiency. 2. Differential diagnosis of Cushing's syndrome. 3. CRH test and Selective Venous Sampling tests for localisation of ACTH source. 4. Monitoring for Nelson's syndrome post bilateral adrenalectomy.

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Sample Type

EDTA, filled to line (1 mL separated plasma). Deliver promptly to the laboratory. Frozen on receipt.

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 1 week

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Testing Frequency

Weekly

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External Notes

It is essential to establish the diagnosis of Cushing's syndrome carefully (with dexamethasone suppression tests etc) before attempting to elucidate the cause, as patients without Cushing's syndrome at all can have ACTH results (including a response to CRH) very like those observed in Cushing's disease. Time of collection must be noted and lab notified to receive sample. A separate simultaneous clotted sample for cortisol assay is usually required.

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Patient Preparation

See protocols for dynamic tests.

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.