Accurate home blood pressure monitors

These devices can be very useful, but sometimes yield inaccurate results.

Hypertension (high blood pressure) is one of the most common of all chronic conditions. Almost a third of all Americans have high blood pressure, and it becomes more common as we grow older. High blood pressure can damage the heart, blood vessels, kidneys, brain and other parts of our body. So it's very important for high blood pressure to be treated.

But in most cases, hypertension has no signs or symptoms. It is often called "the silent killer, " because a person can suffer damage to the body's organs before hypertension is diagnosed. So it's important to have your blood pressure tested often. Most doctors routinely check blood pressure at every appointment, no matter what the reason for your visit.

Home Blood Pressure Monitors

If you have high blood pressure or prehypertension (raised blood pressure that could progress to hypertension), your doctor may ask you to check your blood pressure periodically with a home monitor. Or perhaps, whether you've been diagnosed with high blood pressure or not, you test yourself with a blood pressure kiosk at your pharmacy, gym, or even at the airport. This is great—but be aware that these devices don't always deliver an accurate reading.

Many doctors recommend the use of home blood pressure monitor kits for their patients who have hypertension. This is a good way for the doctor to gain a more accurate understanding of a patient's blood pressure, because blood pressure readings fluctuate. Some people even experience an elevation in blood pressure when at the doctor's office—the so-called "white coat hypertension." The American Heart Association recently recommended that insurance companies reimburse patients for these devices, pointing out that home monitoring not only saves lives, but also saves the insurance companies money.

However, it's important to ensure that your monitor is providing an accurate reading. If you haven't done so already, have your doctor check yours for accuracy. At the 2014 American Society of Nephrology Kidney Week meeting, Dr. Swapnil Hiremath of The Ottawa Hospital and the University of Ottawa presented research comparing the results of home blood pressure monitors with readings from the type of blood pressure monitors used in a doctor's office (called validated mercury sphygmomanometers). Said Dr. Hiremath, "Home blood pressure monitors may be inaccurate in 5 percent to 15 percent of patients. We recommend all patients with home monitors get them validated with their healthcare provider at least once."

Blood Pressure Kiosks

What about drugstore blood pressure kiosks? These too can be useful educational tools, but it's important not to rely exclusively on the results. The U.S. Food and Drug Administration (FDA) recently warned that many people use these kiosks improperly. They may sit in the wrong posture, or position their arm in the cuff improperly. Also, the machine's one-size-fits-all cuff is the wrong size for a percentage of people. Says the FDA, "Using a too-small cuff will result in an artificially high blood pressure reading; a too-large cuff may not work at all, or may result in an inaccurately low blood pressure reading."

Cautions FDA biomedical engineer Stephen Browning, "Hypertension isn't diagnosed solely based on one reading. Inaccurate blood pressure measurements can lead to the misdiagnosis of hypertension or hypotension (low blood pressure) and people who need medical care might not seek it because they are misled by those inaccurate readings."

The FDA says that although blood pressure kiosks have their limitations, they can provide valuable information when used properly and under the guidance of a healthcare provider. FDA biomedical engineer Luke Herbertson, Ph.D., suggests, "Next time you see your doctor, get his or her opinion about whether blood pressure kiosks are right for you and if so, learn to use them properly."