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Test Code CORTF Cortisol, Free, Serum

Important Note

Morning (8 a.m.) specimens are preferred. The 8 a.m. cortisol can be referred to as the a.m. cortisol and can be collected any time between 6 a.m. and 10:30 a.m. in the morning.

Additional Codes

Epic Ordering Code LAB3053096
NBS code LBC11849
Service code 37182

Reporting Name

Cortisol, Free, S

Specimen Type

Serum Red


Necessary Information


Include time of collection.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.25 mL

Collection Instructions:

1. Morning (8 a.m.) specimens are preferred. The 8 a.m. cortisol can be referred to as the a.m. cortisol and can be collected any time between 6 a.m. and 10:30 a.m. in the morning.

2. Centrifuge and aliquot serum into a plastic vial.

Additional Information: If multiple specimens are collected, send a separate order for each specimen.


National University Hospital-Singapore Note:

NUH Outreach Laboratories:
Specimen Requirements
Submit the following:
Container: Red Top
Morning (8 a.m.) specimens are preferred.
Processing Requirements
Centrifuge and aliquot serum into a plastic vial.
Specimen type: Serum
Volume: 1.25 mL
Storage/transport requirements: Refrigerated

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Day(s) Performed

Tuesday, Thursday, Friday

Report Available

2 to 11 days
National University Hospital-Singapore Note:

Please note that this is a referral test requiring transport to the external testing facility and an additional 3-5 days is required.

Reference Values

6-10:30 a.m. Collection: 0.121-1.065 mcg/dL

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Assessment of cortisol status in cases where there is known or a suspected abnormality in cortisol-binding proteins or albumin

 

Assessment of adrenal function in the critically ill or stressed patient, thus preventing unnecessary use of glucocorticoid therapy

CPT Code Information

82530

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CORTF Cortisol, Free, S 2145-1

 

Result ID Test Result Name Result LOINC Value
65423 Cortisol, Free, S 2145-1

Secondary ID

65423

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
National University Hospital-Singapore Additional Information:

Last updated 14/07/2026