Validating a quantitative assay for dexamethasone on LC-MS/MS
Research type
Research Study
Full title
Development and validation of a quantitative assay for measurement of serum cortisol, dexamethasone and prednisolone using LC-MS/MS.
IRAS ID
311554
Contact name
Andrew Davison
Contact email
Sponsor organisation
Royal Liverpool and Broadgreen University Hospitals Trust
Duration of Study in the UK
0 years, 5 months, 30 days
Research summary
Cushing’s syndrome is caused by high levels of cortisol circulating in the blood. Cortisol is a steroid hormone and is produced under the control of the pituitary gland. The frontline test that is used to diagnose Cushing’s syndrome is called the dexamethasone suppression test. Dexamethasone is a steroid similar to cortisol, it is given to the patient at night and their cortisol levels are measured in the morning. If the cortisol has been suppressed overnight this means that the dexamethasone has worked and it proves that the pituitary gland is reacting normally. This is a negative result and means that the patient does not have Cushing’s syndrome. If the result was positive then the cortisol is being produced in an uncontrolled way so the patient does have Cushing’s syndrome.
However, the patient may not take enough dexamethasone or the body may break it down very quickly so it does not have the right effect. This means the cortisol will not be suppressed and so doctors will think the patient has Cushing’s when actually it is the test that has not worked (a ‘false positive’ result).
The steroid drug, prednisolone, acts in a similar way to dexamethasone so can cause the body’s own cortisol levels to be low. If a patient has very low cortisol levels it might be because they are taking prednisolone. If we can measure prednisolone at the same time as measuring cortisol then we will know if their low cortisol is due to prednisolone or if there is another reason for why they have low cortisol.
Being able to measure these steroid drugs at the same time as cortisol will mean patients get the correct diagnosis and won’t have to have extra tests when they don’t need them or have to wait longer for results.REC name
London - South East Research Ethics Committee
REC reference
22/PR/0488
Date of REC Opinion
29 Apr 2022
REC opinion
Favourable Opinion