Cortisol


Sunquest Code:CORT  
Epic Code:LAB61Epic Name:Cortisol
Synonyms:Compound F; Hydrocortisone, Serum; Dexamethasone Suppression Test
Methodology:Chemiluminescent immunoassay
St Johns/St Joseph: CMIA
Turnaround Time:Performed and reported 24 hours/day.


Collection Instructions

Specimen:Blood
Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Container:Red or gold (gel), St Johns/St Joseph/Woodwinds-Green (lithium heparin, no gel) (Red (no gel), St Johns/St Joseph/Woodwinds - Red (no gel))
Collection Instructions:Blood should be collected at 8 AM and 4 PM to evaluate baseline diurnal variation.
Causes for Rejection:Gross hemolysis


Processing and Shipping

Specimen Processing:Centrifuge and aliquot 1.25 mL, 0.2 mL minimum. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature to arrive within 48 hours of collection. Alternatively, ship on dry ice.
Stability:Stability: Room temperature - 8 hours; refrigerated - 48 hours; frozen - indefinitely.
Test Performed at or Referral Lab Chemistry  (UMMC-East Bank, St. Joseph's, St. John's)


Interpretive

Critical Range:> 150.0 μg/dL
St Johns/St Joseph: None
Reference Range:  St Johns/St Joseph:  None
 
Elevated cortisol levels are found in the newborn period. The concentration of serum cortisol attains adult values by the end of the first week of postnatal life and thereafter does not vary with age.
6 mo & older 4-22 μg/dL
8 am blood collection
6 mo & older 3-17 μg/dL
4 pm blood collecion
Dexamethasone Suppression:  1 mg
dexamethasone given at midnight
≤ 5 μg/dL 8 h post dose
8 am blood collection
Coysntropin Stimulation:
30-60 minutes post 25 units I.V.
>20 μg/dL
 
Limitations:Circulating cortisol results from patients receiving Prednisolone or Prednisone therapy may be falsely elevated. Exercise caution with cortisol determinations for patients undergoing therapy with these and structurally related synthetic corticosteroids.
Use:Best used for evaluating adequacy of adrenal or pituitary function.


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