Adrenocorticotropic Hormone

Alias: Corticotropin, ACTH

Specimen Requirement:

Container: 15 ml blood, 3 purple tops (min. vol. = 10 ml whole blood).

Transport: Keep On ice, transport immediately. Separate plasma in refrigerated centrifuge, transfer to ice-cold plastic tube; freeze plasma.

Patient preparation: Patient must fast for at least 10 hours.

Reference Range: <60 pg/ml

Test Availability: Performed Mon.-Fri.from 9:00 a.m. to 3:30 p.m.; results in 7 days.

Clinical Utilization:

1. For differential diagnosis of Cushing's syndrome.
2. For differential diagnosis of adrenal insufficiency.
3. Assisting diagnosis of adrenogenital syndrome.

Method of Analysis: Radioimmunoassay (RIA)

Identifying Codes:

Hermann Test Code: 8300005 =ACTH

CPT Code: 82024 = ACTH

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Interpretation:

ACTH is elevated in Addison's disease (>1000 pg/mL), congenital adrenal hyperplasia, pituitary-dependent Cushing's disease, ectopic ACTH-producing tumors, pseudo-Cushing's states and Nelson's syndrome. Plasma ACTH normally undergoes a diurnal variation with lowest level in late pm. In Cushing's syndrome, the diurnal variation is lost. In Cushing's disease (pituitary-dependent adrenal hyperplasia) and ectopic ACTH -producing tumors, ACTH may be with the normal range, but plasma cortisol is increased. In Cushing's syndrome caused by adrenal adenoma or carcinoma or nodular hyperplasia, plasma cortisol is increased but ACTH is low.

• Functional tests may be used to distinguish ACTH secretion.
• Interfering Substances: Hypoglycemia, insulin, levodopa, metyrapone, vasopressin may increase production of
• ACTH; whereas dexamethasone and other corticosteroids decrease ACTH.
• Sensitivity & Specificity: None Listed.

Literature:

• Orth \D.N. N Engl J Med 1991;;325:957-9.
• Lacroix A., et al. N Engl J Med 1992;327:974-80.
• Loraine, J. A., and Bell, E. T. Hormone Assays and Their Clinical Application. New York, Churchill Liverstone, 1976.