A catecholamine is any organic chemical that contains a benzene ring, two hydroxyl side groups, and an amine. The three most common catecholamines in the human body are adrenaline, norepinephrine and dopamine, Catecholamines can be measured as a whole in a blood test because they are chemically similar. High levels indicate stress. Very high levels can usually indicate injury to the brainstem and are routinely tested for in an emergency room after severe trauma. In a patient without injury, high catecholamine levels indicate a pheochromocytoma.