Hypertension can be difficult to control. If treated promptly, malignant hypertension is often controlled without permanent complications. If it is not treated promptly, complications may be severe and life threatening. Call your health care provider if known hypertension is poorly controlled. A sphygmomanometer is used to measure blood pressure, and is the most accurate method.
Blood pressure is measured against the height of a column of mercury.
This is the most accurate method because it can only be made inaccurate by changing the gravitational constant of the earth.