Cortisol, Random

Message

Do not send original SST collection tube due to short stability of specimen.

Test Code

CORT

Alias/See Also

Epic: LAB61

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL

Minimum Volume

0.3 mL

Other Acceptable Specimens

Specimen Type: Plasma, Lithium heparin
Collection Container: Green top (Lithium heparin)

Instructions

Collection Instructions: Centrifuge and separate cells after clot formation and within 4 hours of collection. Remove serum if testing will be delayed more than 4 hours.

Additional Information:

Baseline samples should be collected between 6 a.m. and 10 a.m. and at least 30 minutes prior to ACTH injection. Injection should be administered no loater than noon, and then 30-minute and 60-minute post injection samples should be collected.
If cortisol stimulation testing is scheduled later in the day, baseline must be collected 30 minutes prior to injection.

Transport Container

Plastic vial

Specimen Stability

Room temperature: Unacceptable
Refrigerated (on gel): 8 hours
Refrigerated (off gel): 14 days
Frozen: 1 month

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Samples stored on gel >4 hours, unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements, cadaver specimens.

Methodology

Chemiluminescent microparticle immunoassay (CMIA)

Setup Schedule

Daily

Report Available

Same day

Limitations

For diagnostic purposes, results should be used in conjunction with other data: symptoms, results of other tests, clinical impressions, etc.
Potentially interfering substances include : Hemoglobin 500 mg/dL; Bilirubin 20 mg/dL; Triglycerides 2000 mg/dL; Total Protein (low/high) 3/10 g/dL
All cortisol measurements should be referenced to the time of day of sample collection due to diurnal variation.
Patients receiving fludrocortisone, prednisolone or prednisone may show artificially elevated cortisol values due to cross–reactivity.

Reference Range

Specimens collected before 10 a.m.: 3.7 - 19.4 µg/dL

Specimens collected after 5 p.m.: 2.9 - 17.3 µg/dL

Clinical Significance

Cortisol is a major glucocorticoid hormone secreted by the adrenal cortex. Its functions include regulation of carbohydrate metabolism and electrolyte and water distribution. Cortisol also has immunosuppressive and anti-inflammatory activity. Cortisol measurements are used as a direct monitor of adrenal status and indirect measure of pituitary hyper or hypofunction. Plasma cortisol levels are highest in the morning and concentrations decrease by half toward evening. Pregnancy or estrogen treatment markedly elevates cortisol levels. Severe stress may also lead to increased cortisol production.

Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031

Last Updated: February 6, 2024
Last Review: N. Wolford, February 6, 2024

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.