Dexamethasone Suppression Cushings

Last Modified: 7/19/2019 4:25:05 PM

Medical Necessity Documentation:  
Client Notes:  
Patient Preparation:

Patient should discontinue taking Biotin, Vitamin B7, or Vitamin H 48 hours before getting blood drawn.

Specimen Requirements: 1.0 mL Serum in a SST Gold Top Tube
Collection Instructions:
Cushing’s Syndrome Method
1.  A dose of 1 mg of Dexamethasone is to be given to the patient at 11:00 P.M.
2.  Request an 8:00 A.M. Cortisol to be drawn the next morning.
Minimum Volume: 0.25 mL
Transport & Storage: Temperature/Stability: 5 days Refrigerated 
3 months Frozen 

24 hours unspun
Reference Range:

0.0 - 1.8 mg/dL

Critical Ranges:  
Test Comments:
In the screen for Cushing’s Syndrome, the Cortisol level will not be suppressed if the disease is present.

Patients taking vitamin supplements containing high doses of biotin (>5 mg/day) may have falsely increased test results generated.
Methodology: Chemiluminescence
Clinical Significance:  
Two methods are acceptable for Dexamethasone Suppression Testing. 
    The first one is used primarily as a screening test for Cushing’s Syndrome (Test Code DSTC1)
    The second is used on psychiatric patients to diagnose depression.(Test Code DST)
Custom Panel: No


Stat Eligible: Yes
Days Performed: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
Sites Performed: Parkview Regional Medical Center
PHL Test Code: DSTC1
EPIC Test Code: LAB2404
Alternate Test Names: Cushings; Dexamethasone Suppression for Cushings
Included Tests: 8am Cortisol
CPT Coding: 82533

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