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Cortisol PM
MessageCollect between 15:00 - 17:00
Do not send original SST collection tube due to short stability of specimen.
Do not send original SST collection tube due to short stability of specimen.
Test Code
CORTP
Alias/See Also
Epic: LAB9800
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL
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:
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
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.
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
2.9 - 17.3 ug/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