The main test for high blood pressure is simple, fast, and painless. These are the usual steps:
You sit quietly for 5 minutes before the test, with both feet flat on the floor.
You sit down with your arm resting on the arm of the chair so that your arm is level with your heart.
An inflatable sleeve, called a cuff, is wrapped around your upper arm. It's attached to a dial that will show your blood pressure numbers.
The nurse (or other health professional) seals the cuff and pumps it up. You feel tight pressure as the cuff cuts off the blood flow in your arm.
Next, the nurse slowly loosens the cuff while using a stethoscope to listen to the heartbeat in your inner elbow. When the cuff is just loose enough that blood starts to flow again and the nurse can hear it, that is your systolic blood pressure.
The cuff is slowly loosened some more. When it's loose enough that your heartbeat can no longer be heard through the stethoscope, that is your diastolic blood pressure.
If this test shows that your blood pressure is high, your doctor will likely have you come in for a follow-up visit to be tested again. This will confirm that you have high blood pressure.