High blood pressure is known as the silent killer because it has no symptoms and many people do not know that they have it. The only way to determine if you have high blood pressure is to have it tested. There are two common types of blood pressure testing devices. A sphygmomanometer (SFIF’mo-mah-NOM’eh-ter) is a manual testing device, found typically in doctor's offices and in homes. Automatic blood pressure testing devices are found in grocery stores, pharmacies and shopping centers. Both tests measure systolic and diastolic pressure in millimeters of mercury (mm Hg). A blood pressure measurement is presented as systolic pressure over diastolic pressure. For example, if systolic blood pressure is measured at 118 mm Hg and diastolic blood pressure is 79 mm Hg, blood pressure is recorded at 118/79, or 118 over 79. To learn more about blood pressure tests, see The Guide to Blood Pressure Tests.