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HelpTest ID ACTH Adrenocorticotropic Hormone (ACTH), Plasma
Useful For
Determining the cause of hypercortisolism and hypocortisolism
Method Name
Automated Chemiluminescent Immunometric Assay
Reporting Name
Adrenocorticotropic Hormone, PSpecimen Type
Plasma EDTACollection Container/Tube: Ice-cooled, lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Morning (6 a.m.-10:30 a.m.) specimen is desirable.
2. Spin down in a refrigerated centrifuge and immediately separate plasma from cells.
3. Immediately freeze plasma.
Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)
Oncology Test Request Form (T729) (http://www.mayomedicallaboratories.com/it-mmfiles/oncology-request-form.pdf)
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma EDTA | Frozen | 14 days |
Clinical Information
Adrenocorticotropic hormone (ACTH), the primary stimulator of 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 levels exhibit peaks (6-8 a.m.) and nadirs (11 p.m.).
Cortisol, the main glucocorticoid, plays a central role in glucose metabolism and in the body's response to stress. Only a small percentage of circulating cortisol is biologically active (free form), with the majority of cortisol inactive (protein bound). Cortisol is inactivated in the liver and excreted in the urine as conjugated compounds (largely 17-hydroxysteroids). Urine free cortisol levels reflect circulating free plasma cortisol levels.
Disorders of cortisol production:
Hypercortisolism
-Cushing syndrome:
- Cushing disease (pituitary ACTH-producing tumor)
- Ectopic ACTH-producing tumor
- Ectopic CRH
- Adrenal cortisol-producing tumor
- Adrenal hyperplasia (non-ACTH dependent, autonomous cortisol-producing adrenal nodules)
Hypocortisolism
-Addison disease-primary adrenal insufficiency
-Secondary adrenal insufficiency
-Pituitary insufficiency
-Hypothalamic insufficiency
-Congenital adrenal hyperplasia-defects in enzymes involved in cortisol synthesis
Reference Values
10-60 pg/mL (a.m. draws)
No established reference values for p.m. draws
Pediatric reference values are the same as adults, as confirmed by peer reviewed literature.
Petersen KE: ACTH in normal children and children with pituitary and adrenal diseases. I. Measurement in plasma by radioimmunoassay-basal values. Acta Paediatr Scand 1981;70:341-345
Cautions
In very rare instances of the ectopic adrenocorticotropic hormone (ACTH) syndrome, the elevated ACTH may be biologically active but not detected by the immunometric assay.
Patients taking glucocorticoids may have suppressed levels of ACTH with an apparent high level of cortisol. This may be due to cross-reactivity with the cortisol immunoassays. If exogenous Cushing is suspected, a cortisol level determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) (eg, COR / Cortisol, Serum, LC-MS/MS) should be used with the ACTH level for the interpretation.
Day(s) Performed
Monday through Friday; 5 a.m.-12 a.m., Saturday; 6 a.m.-6 p.m.
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82024