Ronald Reagan UCLA Medical Center Clinical Laboratory
Performing Section
Chemistry
Availability
Daily
Turnaround Time
Routine: 4 hours from receipt in the laboratory; STAT: 1 hour from receipt in the laboratory
Methodology
Electrochemiluminescence
Use
Pituitary function test useful in the differential diagnosis of Cushing's syndrome, the ectopic ACTH syndrome (eg, carcinoma of lung, islet cell tumors, carcinoid tumors, medullary carcinoma of thyroid), adrenal insufficiency, Addison's disease, hypopituitarism, ACTH-producing pituitary tumors (eg, Nelson's syndrome), and androgenital syndrome
Patient Preparation
Whenever possible patient should stop taking supplements containing high concentrations of biotin (vitamin B7) for at least 12 hours prior to blood collection. Overnight fasting sample preferred.
Limitations
High concentrations of biotin in patient's blood may lead to falsely decreased ACTH results. The ACTH level may be elevated by stress, and is subject to diurnal variation. Most secretion occurs in the morning and late PM levels are approximately 50% of early AM levels. Dilantin® and glucocorticoid therapy will depress ACTH. In patients who have received preparations of mouse monoclonal antibodies for diagnosis or therapy, human anti-mouse antibodies (HAMA) may be found in quantities which may cause interference in this assay.
Additional Information
ACTH levels in Cushing's disease (pituitary) may be elevated or high normal (inappropriately elevated for plasma cortisol level). ACTH levels in ectopic ACTH syndrome are usually quite high. In Cushing's syndrome due to adrenal adenoma or carcinoma ACTH levels are very low to undetectable while plasma cortisol is increased. In primary adrenal insufficiency (ie, Addison's disease) and in Nelson's syndrome, ACTH plasma concentrations are consistently elevated and cortisol is decreased. In androgenital syndromes, ACTH is increased and plasma cortisol is decreased. For sequential follow-up, specimen should always be drawn at the same time each day, most preferably at 0800.
Specimen Type
Whole blood
Container
Lavender/EDTA Lavender/EDTA Microtainer
Collection Instructions
Place on ice. Send to the Laboratory immediately.
Volume
3 mL blood (1.5 mL plasma)
Minimum Volume
1 mL blood (0.5 mL plasma)
Shipping and Handling Instructions
Separate plasma and freeze.
Ambulatory Specimen Processing / Transport
Immediately after collection, spin the sample, then separate the plasma into a transport vial. Freeze immediately. Transport frozen.
Causes for Rejection
Gross hemolysis Sample received in laboratory at room temperature (not on ice)
Reference Range
Male: 6-59 pg/mL Female: 4-48 pg/mL
Test Information
CPT Codes
82024
Synonyms
Adrenal Corticotropin
Adrenocorticotropic Hormone
Corticotropin
Performing Laboratory / Facility
Ronald Reagan UCLA Medical Center Clinical Laboratory
Performing Section
Chemistry
Availability
Daily
Turnaround Time
Routine: 4 hours from receipt in the laboratory; STAT: 1 hour from receipt in the laboratory
Methodology
Electrochemiluminescence
Use
Pituitary function test useful in the differential diagnosis of Cushing's syndrome, the ectopic ACTH syndrome (eg, carcinoma of lung, islet cell tumors, carcinoid tumors, medullary carcinoma of thyroid), adrenal insufficiency, Addison's disease, hypopituitarism, ACTH-producing pituitary tumors (eg, Nelson's syndrome), and androgenital syndrome
Patient Preparation
Whenever possible patient should stop taking supplements containing high concentrations of biotin (vitamin B7) for at least 12 hours prior to blood collection. Overnight fasting sample preferred.
Limitations
High concentrations of biotin in patient's blood may lead to falsely decreased ACTH results. The ACTH level may be elevated by stress, and is subject to diurnal variation. Most secretion occurs in the morning and late PM levels are approximately 50% of early AM levels. Dilantin® and glucocorticoid therapy will depress ACTH. In patients who have received preparations of mouse monoclonal antibodies for diagnosis or therapy, human anti-mouse antibodies (HAMA) may be found in quantities which may cause interference in this assay.
Additional Information
ACTH levels in Cushing's disease (pituitary) may be elevated or high normal (inappropriately elevated for plasma cortisol level). ACTH levels in ectopic ACTH syndrome are usually quite high. In Cushing's syndrome due to adrenal adenoma or carcinoma ACTH levels are very low to undetectable while plasma cortisol is increased. In primary adrenal insufficiency (ie, Addison's disease) and in Nelson's syndrome, ACTH plasma concentrations are consistently elevated and cortisol is decreased. In androgenital syndromes, ACTH is increased and plasma cortisol is decreased. For sequential follow-up, specimen should always be drawn at the same time each day, most preferably at 0800.
Specimen Collection and Handling
Specimen Type
Whole blood
Container
Lavender/EDTA Lavender/EDTA Microtainer
Collection Instructions
Place on ice. Send to the Laboratory immediately.
Volume
3 mL blood (1.5 mL plasma)
Minimum Volume
1 mL blood (0.5 mL plasma)
Shipping and Handling Instructions
Separate plasma and freeze.
Ambulatory Specimen Processing / Transport
Immediately after collection, spin the sample, then separate the plasma into a transport vial. Freeze immediately. Transport frozen.
Causes for Rejection
Gross hemolysis Sample received in laboratory at room temperature (not on ice)
