Adrenocorticotropic Hormone (ACTH), Plasma
Also known as: ACTH, Corticotropin
Use
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)
Special Instructions
Instructions for suppression/stimulation tests involving ACTH measurement can be found in the online endocrine appendices. This test may exhibit interference when the sample is collected from a person consuming a high dose of biotin. Patients should be cautioned to stop biotin intake at least 72 hours before sample collection.
Limitations
ACTH secretion is pulsatile; multiple specimen collections may be required. Non-siliconized tubes can lead to low results. Monoclonal mouse antibodies and high titers of antibodies to streptavidin and ruthenium can cause interference. Collection time is crucial due to diurnal variation.
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 2141-0
- 2141-0
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.8 mL
Minimum Volume
0.3 mL
Container
Plastic or siliconized glass lavender-top (EDTA) tube
Collection Instructions
ACTH should be drawn between 7 a.m. and 10 a.m. Collect into iced plastic or siliconized glass lavender-top (EDTA) tube, noting the time. After venipuncture, immerse tubes in an ice bath. Separate plasma by centrifugation within one hour, transfer to a Labcorp PP transpak frozen purple tube, and freeze immediately.
Patient Preparation
Ensure that patients discontinue biotin supplementation at least 72 hours before sample collection.
Storage Instructions
Freeze immediately.
Causes for Rejection
Thawed specimen; serum or heparinized plasma specimen; specimen collected in non-siliconized glass tube
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unstable |
| Refrigerated | Unstable |
| Frozen | 14 days |