You may have heard about "white coat hypertension" - elevated blood pressure readings that occur only when the measurements are made in a doctor's office. You can tell if you have white coat hypertension by checking your blood pressure at home with a blood pressure monitor and comparing it to readings taken at your doctor's office.

My wife's doctor didn't tell her she had high blood pressure, but he recommended a special test because blood pressures were significantly different in her two arms. Checking her blood pressure with a home blood pressure monitor several times throughout the day over a two-week period, I never found a significant difference in pressures between the two arms.

Although many different types of home blood pressure monitors are available, the best choice is a digital automatic cuff that is wrapped tightly around your arm about 1 inch above the crease at your elbow.

A touch of a button inflates the cuff, which then automatically deflates. The digital display shows your systolic (the number on top) and diastolic (the number on the bottom) pressures. The cost is reasonable, between $50 and $100.

These monitors have different cuff sizes, and the size of your arm may require a larger or smaller than average cuff size to get an accurate reading. (Unfortunately, many doctors get inaccurate blood pressure readings because they use the same cuff for all patients.) Before purchasing a monitor, ask your doctor or the office nurse what size cuff you need.

I don't recommend purchasing a monitor that measures blood pressure at the wrist or fingertips or a manual device. The wrist and fingertip models are not reliable and the manual devices are too complicated for many people to use. They have a cuff connected by a rubber tube to a gauge which records the blood pressure. You must inflate the cuff by pressing on a bulb connected to the tubing and listen with a stethoscope to changes in blood sounds as you deflate the cuff.

Before using your home monitor, get your doctor or office nurse to show you how it works and to test its accuracy.