A patient suspected of having Cushing disease is scheduled for dexamethasone suppression testing. Which statement indicates need for further teaching?

A patient suspected of having Cushing disease is scheduled for dexamethasone suppression testing. Which statement indicates need for further teaching?

• A. My blood will be drawn over 3 days.
• B. The test is done with a single blood draw.
• C. I will not need to fast.
• D. I will be given a medication at bedtime.

Answer: (A)

Dexa suppression testing is designed to see if cortisol production can be shut down by a small dose of dexamethasone given at night. In the common overnight protocol, you take dexamethasone at about bedtime and have a single blood cortisol level drawn the next morning. If cortisol stays high, it suggests endogenous Cushing syndrome; if it drops appropriately, suppression occurs and the result helps differentiate causes. Saying blood will be drawn over 3 days isn’t how this test is usually done, which is why that statement signals the need for teaching. The standard approach uses one morning blood draw after the overnight dose. The other statements fit with the typical plan: you receive the medication at bedtime, and you don’t necessarily have to fasting beforehand, since no special fasting is usually required.

Dexa suppression testing is designed to see if cortisol production can be shut down by a small dose of dexamethasone given at night. In the common overnight protocol, you take dexamethasone at about bedtime and have a single blood cortisol level drawn the next morning. If cortisol stays high, it suggests endogenous Cushing syndrome; if it drops appropriately, suppression occurs and the result helps differentiate causes.

Saying blood will be drawn over 3 days isn’t how this test is usually done, which is why that statement signals the need for teaching. The standard approach uses one morning blood draw after the overnight dose. The other statements fit with the typical plan: you receive the medication at bedtime, and you don’t necessarily have to fasting beforehand, since no special fasting is usually required.