Cortisol

Clinical Chemistry

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Description

Cortisol is the major glucocorticoid. It is secreted by the adrenal glands in response to ACTH from the pituitary. Cortisol is involved in glucose regulation and also has anti-inflammatory properties. Excess endogenous cortisol causes Cushing's syndrome. This may be due to adrenal disease, pituitary disease (excess ACTH) or ectopic ACTH production. The clinical features of Cushing's are numerous, the features which best distinguish Cushing's syndrome are proximal myopathy, easy bruising, facial plethora and striae. Insufficient cortisol is due to adrenal disease or pituitary disease (lack of ACTH). The clinical features are; fatigue, weight loss, anorexia, abdominal pain, diarrhoea, postural hypotension and pigmentation (only when due to adrenal disease). If either condition is suspected the patient should be discussed with Endocrinology.

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Indications

1. Investigation of Addision's syndrome (lack of cortisol).

2. Investigation of Cushing's syndrome (excess cortisol).

3. Investiation/monitoring of pituitary disease.

4. Assessment of adrenal reserve in patients treated with steroids.

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Sample Type

Serum SST/Gel, Minimum 2mL (1mL separated serum)

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 1 day

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Testing Frequency

As required

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External Notes

STH guideline for investigation of possible hypoadrenalism of inpatients. Due to the lack of availability and high cost of Synacthen (tetracosactide), an STH guideline for investigation of inpatients with possible hypoadrenalism has been produced to reduce any inappropriate usage of this product in the Short Synacthen Test'. The guidance is available on the STH intranet and is called: 'Hypoadrenalism - Investigation of Possible Hypoadrenalism for Inpatients' http://nww.sth.nhs.uk/STHcontDocs/STH_CGP/Endocrinology/HypoadrenalismInvestigationGuideline.docx

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Patient Preparation

If the patient is on prednisolone they will need to be switched to dexamethasone 24 hours before measuring cortisol, as prednisolone is detected by the cortisol assay.

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.