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Cortisol – Free by LC/MS, Serum

Test ID: FCORTQST S

Test

Method

Chromatography/Mass Spectrometry

Specimens

Serum

Clinical Utility

Free cortisol is useful in the detection of patients with Cushing’s syndrome for whom free cortisol concentrations are elevated.

Test Version

19-Nov-2025

Specimen

Specimens

Serum

Collection Containers

Preferred

Red top (no additive)

Acceptable

Lavender top (EDTA)

Sample Volume

2.0 mL

Minimum Volume

0.7 mL

Stability

Ambient 2 days
Refrigerated 7 days
Frozen 730 days

Rejection Criteria

Hemolysis Gross
Specimen Gel Separator tube

Test Version

19-Nov-2025

Performance / Interpretation

Method

Chromatography/Mass Spectrometry

Turnaround Time

12 days

Results

Name Units Reference Range Conversion Factor
CORTISOL,FREE mcg/dL
  • Adult:
  • 8:00 - 10:00 A.M.: 0.07 - 0.93
  • 4:00 - 6:00 P.M.: 0.04 - 0.45
  • 10:00- 11:00 P.M.: 0.04 - 0.35

Test Version

19-Nov-2025

Interface / Setup

HL7 Interface Codes

Order Code Result Codes Units
FCORTQST S 66072CORTISOL,FREE,LC/MS,S mcg/dL

Test Version

19-Nov-2025