Cortisol, Free, Serum
Use
This test is useful for assessing cortisol status in cases with known or suspected abnormalities in cortisol-binding proteins or albumin. It also evaluates adrenal function in critically ill or stressed patients, aiding in the avoidance of unnecessary glucocorticoid therapy. Cortisol, the main glucocorticoid, is pivotal in glucose metabolism and stress response. Disorders like Cushing disease and Addison disease stem from cortisol imbalance. Additionally, free cortisol measurements circumvent issues in total cortisol estimation due to variations in cortisol-binding globulin and albumin levels.
Special Instructions
Morning specimen collection (6 a.m. to 10:30 a.m.) is preferred for accurate results. Ensure centrifugation and serum aliquoting into a plastic vial. In cases of multiple specimen submissions, each requires a separate order.
Limitations
Cortisol levels increase with pregnancy and exogenous estrogens. The test is not FDA approved, developed under CLIA requirements. However, free cortisol baseline values should not exclude adrenal insufficiency due to low performance. Further study is necessary to determine glucocorticoid management in stressed patients.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 2145-1
- 2145-1
Result Turnaround Time
2-11 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.25 mL
Minimum Volume
1 mL
Container
Red top, Plastic vial
Collection Instructions
Specimens should be collected in the morning between 6 a.m. and 10:30 a.m. Centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Gross hemolysis, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 28 days |
| Refrigerated | 28 days |
| Frozen | 28 days |