Are those drugstore blood-pressure machines really accurate?

By: Dr. Michael Martin

High blood pressure (also called hypertension) is one of the biggest health problems for my patients -- and Americans in general. So I routinely recommend that patients keep track of their blood pressure by taking readings at home between doctor visits. If you don’t have your own BP machine, you can get one at the drugstore.

In my experience, drugstore blood-pressure machines are fairly accurate. But it’s important to understand that they are one-size-fits-all. They have to be able to accommodate a tiny woman as well as a large man. And using a BP cuff that’s too small for your arm can cause falsely high readings.

I prefer that patients managing hypertension use their own personal sphygmomanometers (BP machines) at home and write the measurements on a spreadsheet, including the date and time of the reading, so I can get a sense of how their pressure changes throughout the day. Personal BP machines are relatively inexpensive. One advantage of using your own is that you can bring it to your doc’s office to be calibrated, so you’re certain to be accurate.

If you do buy a drugstore machine, make sure to use it properly:

• Check your pressure right after seeing the doctor; that way you can use the blood pressure reading at the drug store as a baseline to see if the machine is on target.
•  Sit for at least five minutes before taking the reading, as changes in physical activity can affect pressure.
• If either the systolic pressure (top number) or diastolic pressure (bottom number) differs by more than 10 mmHg from the reading at your doctor’s office, you should alert the store and find another machine somewhere else.
• If your pressure is significantly higher than your usual numbers at two different store machines, call your doctor ASAP.

Photo Credit: @iStockphoto.com/kasoga Expert Q&A Archive

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