Are there any tests that check whether the adrenal medulla is functioning normally?

Yes: The Adrenal Medulla Secretes Adrenaline, (epinephrine, norepinephrine). Flight or Fight response. If your doctor is concerned (condition resulting in an abnormal or increase secretion). They can check hormones via blood and urine tests. The endocrinology doctor will follow this if you have abnormalities. These are not routine screening tests. They are done if there is a clinical indication (sxs)