A blood pressure test measures the pressure in your arteries as your heart pumps. You might have a blood pressure test as a part of routine doctor's appointment or as a screening for high blood pressure (hypertension). Many people, such as those with high blood pressure, do their own blood pressure tests at home so that they can better track their health.You may have frequent blood pressure tests if you've been diagnosed with prehypertension, high blood pressure (hypertension) or low blood pressure (hypotension).