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.

Lavender (EDTA), 4mL

Specimens for ACTH should be collected between 7 and 10am.

1. Collect into iced plastic or siliconized glass lavender-top (EDTA) tube, noting time of collection.
2. After venipuncture, immediately immerse the tubes in an ice bath.

1. Spin within one (1) hour of sample collection
2. Immediately transfer the plasma into a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp).
3. Freeze immediately and maintain frozen througout transport.

To avoid delays in turnaround time when requesting multiple tests on frozen samples, submit a separate frozen aliquot for each test requested.

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Frozen (strict) - 14 days

Freeze/thaw cycles - Stable x 1

• Thawed specimen
• Serum or heparinized plasma specimen
• Specimen collected in nonsiliconized glass tube

Electrochemiluminescence immunoassay (ECLIA)

7.2 - 63.3 pg/mL for samples collected between 7 and 10am