Pituitary function test useful in the differential diagnosis of Cushing syndrome, ectopic ACTH syndrome (eg, carcinoma of lung, islet cell tumors, carcinoid tumors, medullary carcinoma of thyroid), Addison disease, hypopituitarism, and ACTH-producing pituitary tumors (eg, Nelson syndrome)
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R).
It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
Specimens for ACTH should be collected between 7 and 10am.
To avoid delays in turnaround time when requesting multiple tests on frozen samples, submit a separate frozen aliquot for each test requested.
Frozen (strict) - 14 days
Freeze/thaw cycles - Stable x 1
Electrochemiluminescence immunoassay (ECLIA)
7.2 - 63.3 pg/mL for samples collected between 7 and 10am