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Alias: N/A

Discipline: Clinical Chemistry

Test information: Cortisol is the most abundant circulating steroid and the major glucocorticoid secreted by the adrenal cortex. Physiologically effective in anti-inflammatory activity and blood pressure maintenance, cortisol is involved in gluconeogenesis, calcium absorption and the secretion of gastric acid and pepsin. As an indicator of adrenocortical function, measurement of blood cortisol levels is useful in the differential diagnosis of Addisons and Cushings disease, hypopituitorism and adrenal hyperplasia and carcinoma. A variety of stimulation and suppression tests (ACTH, dexamethasone) can supply supportive information on adrenocorticol function.

Specimen Type(s)
  • Blood;
Other Acceptable Specimen Type(s)
Specimen Container - Adult
  • Gold Top SST BD;
Specimen Container - Paediatric
  • Light Green Top Microtainer BD;
  • N/A;
Part of a test profile?
Volume (min) of sample to be sent to laboratory
Patient Preparation, Sample Handling and Transport
Sample should be taken at 8am
Maximum add on time
5 days
Units and Reference Ranges / Interpretation
"Between 8 and 9 am: <100 nmol/L is suspicious of adrenal insufficiency and requires further investigation.
100-400 nmol/L is not diagnostic of adrenal insufficiency and should be interpreted in light of clinical symptoms.
>400 nmol/L adrenal insufficiency unlikely " - nmol Adrenal insufficiency will be indicated by a cortisol of <440 nmol/L at 30 mins post Synacthen - nmol Dexamethsone <50 nmol/L
UKAS number
UKAS accredited test?

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Last updated: 03-05-2024