R U H Bath, return to home page

Pathology Departments Requesting & Reporting Blood Test Information Phlebotomy Guide Contact us
Blood Sciences

Blood Test Information

Cortisol
 
minimum sample volume required ~ 5ml

  back to assay index

Special instructions
If performing a short synacthen test, please collect all samples and send together.

Reference range
Please see individual reports for interpretation.

Units
nmol/L

Turnaround Time
2 days

Department: Biochemistry

Clinical Application
Measurement of cortisol is most useful as part of a dynamic function test. Low random cortisols (especially from around 9am) may indicate cortisol deficiency: if this is suspected a short synacthen test should be performed (the test has no place in assessment of suspected Cushing's syndrome). Measurement of random cortisol is unhelpful in the investigation of suspected Cushing's syndrome, where either a 24-hour urine free cortisol measurement or an overnight dexamethasone suppression test should be used. Serial cortisol measurements are used to check adequacy of cortisol replacement therapy ("cortisl day curves"). Test limitations: Prednisolone, methylprednisolone or prednisone may cause falsely elevated cortisol results. PLEASE NOTE: As of 07.12.15, new method for serum cortisol. Results will be on average 24% lower than previously. Please contact clinical staff in biochemistry if you wish to discuss further (ext 4713/15/11).

 
 

back to top