Diagnosis 

Falsely high pressure can result from:

• An arm cuff that is too small
• Talking during the test
• Recently consuming foods or beverages (such as coffee) that raise blood pressure

Office blood pressure readings taken by a doctor are more likely to be higher than readings measured at home. This so-called white-coat hypertension requires additional readings by a nurse or by the patient. Home monitoring improves the accuracy of a simple office measurement. An average of all the measurements will be considered in the diagnosis of hypertension. If high normal or high blood pressure persists, further tests should be performed to determine if the organs are affected.

Other Blood-Pressure Monitors. Alternative pressure-measuring aneroid and electronic devices are available. Aneroid instruments are round, compass-like devices that use a metal spring to measure blood pressure and are often used by doctors. Electronic devices are typically used for home monitoring.

Home Monitoring

Monitoring Equipment. A number of home tests are available for checking blood pressure between doctor visits. A doctor may loan a patient a portable unit that records blood pressure during a full day's activity. This test, known as ambulatory monitoring, is particularly useful for those who experience wide blood pressure swings, such as those who have white-coat hypertension or show resistance to drug therapy. According to one study, accurately measuring blood pressure at home over a full day was a significantly better predictor of cardiovascular risk than standard office-based measurements. To improve clinical outcomes, devices are now available that allow 24-hour ambulatory blood pressure monitoring and electronically store results for analysis by the doctor. It is not clear if their added benefits justify their expense, however.

Cuffs and Stethoscopes. Manual cuffs and stethoscopes are fairly accurate, but they require practice to use. The cuff must be the right size (one size does not fit all). Devices that use a digital readout and a cuff that can be electronically inflated and deflated are proving to be as accurate as a stethoscope.