Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
ACTH (ADRENOCORTICOTROPIC HORMONE) - (P)
Test Code: ACTH
Clinical Information:
Description: ACTH testing is used in the assessment of disorders of cortisol deficiency or excess.

 

ACTH is produced in the anterior pituitary in response to corticotropin-releasing hormone (CRH) released by the hypothalamus. ACTH stimulates the formation and secretion of glucocorticoids (especially cortisol) by the adrenal cortex.

 

Plasma ACTH and cortisol levels show a diurnal variation with peaks at 6:00 - 8:00 AM and troughs at 11:00 PM. ACTH results should always be evaluated with simultaneously measured cortisol levels as ACTH concentrations vary considerably depending on physiological or pathological conditions.


Test Indications: This test is used to measure ACTH level and should not be confused with the “ACTH (Cosyntropin) Stimulation test” used to measure cortisol response to ACTH administration.


Patient Preparation Instructions: Multivitamins (45–125 µg biotin) or biotin-only supplements up to 1 mg per day do not interfere with this test. Samples should not be taken from patients receiving therapy with high biotin doses (i.e. >5 mg/day) until at least 8 hours after the last dose.


See F10-50-45D Approved Physicians for Specialist Endocrinology Requisition
Collection Devices:
Collect in chilled tube, ON ICE. Collect specimen between 0800-1000 h, record exact time.
Specimen Required:


Plasma: 2.0 mL
Pediatric Plasma: 0.5 mL

Collection Information: 

Collect in chilled tube, ON ICE.

Centrifuge at ~4°C, transfer plasma to aliquot tube and freeze immediately.

Collect specimen between 0800-1000 h, record exact time.
 

Specimen Stability: 
Ambient: not stable

Refrigerated: 3 hours 
Frozen: 10 weeks at -20oC (freeze only once)

Thawed samples kept at 2 – 8 °C must be tested within 3 hours
Referral:
Plasma: 2.0 mL
Pediatric Plasma: 0.5 mL

Shipping & Storage: Plasma must be transferred to an aliquot tube and stored/shipped frozen

DO NOT ship whole blood.

Thawed samples are not suitable for testing.

 

See #110-10-05 Serum / Plasma Separation Procedure & Transport


Testing Laboratory (MB): Send specimen to Health Sciences Centre - MS5
Requisition:
Reference Values:
Reference Intervals: 

1 – 13 pmol/L

Reference intervals are applicable to morning (7h00-10h00) collection.

 

Method of Analysis: DiaSorin Chemiluminescence
Availability:
Within 1 Week
See Also:
More Information:
Interpretation & Assay Interferences: The assay is not affected by concentrations of bilirubin up to 10 mg/dL, hemoglobin up to 500 mg/dL, or triglycerides up to 3000 mg/dL.

 

Although HAMA-neutralizing agents are added, extremely high HAMA (human anti-mouse antibodies) concentrations may occasionally influence results.

 

Assay demonstrates negligeable/undetectable cross-reactivity with the following compounds: ACTH (1-10), ACTH (1-24), ACTH (18-39), ACTH (11-24), alpha-NSH, beta-MSH, beta-endorphin, somatostatin, neurotensin, enkephalin.