How many tests are usually needed to confirm Cushing's disease in a fe...

One needs a clinical suspicion of Cushing's syndrome and the 24h urine test can support this with evidence of high cortisol levels.
Then it needs evidence of elevated, somewhat autonomous, cortisol levels and a reliable way to do that is with a dexamethasone suppression test, which takes 2 days.
If that test shows cortisol that fails to suppress after the dexamathasone, then one must measure cortisol and ACTH (at 9am). The ACTH is quite difficult to sample and measure, it usually takes a week or two from when it is taken. If the cortisol is high with detectable/ high ACTH then one must go on to look where the ACTH is from. This usually requires sampling from the blood veins that drain the pituitary; it is a very specialised test and can take weeks to set up in one of the centres that do it, often needing a repeat evaluation before performing it +/- CT chest and MRI pituitary.
Cushing's disease can be very difficult to diagnose.

Related questions

Other questions answered by Doctoralia's experts:

Do you have a question about Cushings disease?

Our experts answered the following question about Cushings disease:

Ask thousands of Doctoralia experts anonymously and for free

  • Your question will be published anonymously
  • Make it one, clear, medical question
  • Be brief
  • This service doesn´t replace a consultation with a medical professional. If you have a problem or emergency, go to a doctor or an emergency room.
  • Questions about a specific case or second opinion requests will not be allowed.
In order to improve our service we are using our own and third-party cookies. By continuing to use this site, you agree to our cookie policy. More info X