Are Home Blood Pressure Monitors Accurate? – Cleveland Clinic

Maybe your blood pressure has been creeping up over time, or you’re starting treatment for hypertension. Your doctor suggests you buy a home blood pressure monitor to help keep track between office visits. Simple enough, right?

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Maybe not. A quick check online reveals hundreds of different models — and even a bunch of apps for your smartphone. How do you even start to sort through all that without, well, spiking your blood pressure?

Don’t worry, we’ve got you covered. Heart and hypertension specialist Luke Laffin, MD, has six tips on what you need — and what you don’t need — in a home blood pressure monitor.

How to monitor blood pressure at home

Before we dive into Dr. Laffin’s tips, let’s review how to take your blood pressure at home. The American Heart Association has a few suggestions to make sure your readings are accurate:

  1. Avoid activities that raise blood pressure 30 minutes before testing. That means no caffeine, cigarettes or exercise.
  2. Positioning matters. When you’re testing your blood pressure, you need to pay attention to your posture. Sit upright with your back supported, and make sure your arm is raised to heart level. Your arm should be supported by something like a cushion or armrest.
  3. Chill out a bit. Try to relax for five minutes before turning the monitor on. Chatting with friends, checking your phone — anything that could stress you out or get you excited, really — can impact the accuracy of your reading.
  4. Don’t hold it. Weird fact of the day: Needing to pee raises your blood pressure! That’s another reason (though, we hope you didn’t need one) to make time for a bio-break.
  5. Have a routine. Blood pressure fluctuates a lot during the day, so you’re most likely to get useful data if you test at roughly the same times every day. Notice the “s” there: Testing once a day won’t give you or your doctor the same kind of insight that you’ll get from checking several times a day at consistent times.

Of course, you can do everything right and still get an inaccurate blood pressure reading if you’re working with a sub-par monitor.

What to consider when choosing a monitor

With so many blood pressure monitors on the market, how do you decide what to pick? And how do you know that your monitor’s working properly? Dr. Laffin says you need to keep six things in mind.

Choose arm cuffs over wrist cuffs

You can purchase a blood pressure monitor at any drugstore or online. No matter where you buy yours, Dr. Laffin recommends getting a monitor with an automatic cuff that wraps around your upper arm. It’s called a brachial blood pressure monitor.

“Don’t get one where you need a stethoscope,” he advises. “An automatic cuff is best.”

What about those monitors with wrist cuffs? Or finger cuffs? The American Heart Association recommends against both for people who are able to use an arm cuff. It’s the best option and tends to provide the most accurate readings.

Size matters

The size of the cuff is the most important feature to check when you’re selecting a blood pressure monitor, Dr. Laffin notes. In fact, a 2023 study found that “miscuffing” resulted in “strikingly inaccurate BP measurements.”

The size you need is determined by the circumference of your upper arm. A cuff that doesn’t fit properly may give you inaccurate readings, leading to a misdiagnosis.

Right about now you may be thinking, what about the one-size-fits-all options that many home monitors offer? They aren’t terrible, but they also aren’t as reliable as cuffs that are fitted to the size and shape of your arm. This is one of those situations where it’s worth it to pull out the tape measure. You need to measure the circumference of the middle of your arm — exactly halfway between your shoulder and elbow.

The different cuff sizes are:

  • Adult small: Arm circumference of 22 to 26 centimeters (about 8.5 to 10 inches).
  • Adult average: Arm circumference of 27 to 34 centimeters (about 10.5 to 13 inches).
  • Adult large: Arm circumference of 35 to 44 centimeters (about 13.5 to 17 inches).
  • Adult extra-large: Arm circumference of 45-52 centimeters (about 17.7 to 20.5 inches).

Keep it simple

Forget the bells and whistles. They boost the cost of the monitor and are often unnecessary.

Sure, Bluetooth connectivity and storing your readings in the cloud are cool features, but you don’t really need them.

“You shouldn’t have to pay more than $40 to $60 for an appropriate, physician-approved blood pressure monitor that will do the job just fine,” Dr. Laffin says.

Skip the apps

If you look at any app store, you’re likely to find dozens of blood pressure measurement apps for your smartphone.

Dr. Laffin is blunt: “These products don’t work and have not been rigorously tested.”

Certain apps claim to measure your blood pressure through pulse wave velocity, which essentially looks at the wave form in the artery of your finger.

“But those are often inaccurate,” he continues. The last thing you want is to obtain false information and be falsely scared — or falsely reassured — about your blood pressure numbers.

Check for validation and inspect for accuracy

By now, you might be feeling a bit overwhelmed by all the things you need to keep in mind when selecting a monitor. After all, there are so many brands out there.

Have no fear: There’s a website out there that can help cull that list for you!

It’s called the US Blood Pressure Validated Device Listing. This independent review committee tests blood pressure monitoring products for accuracy and gives specific models their stamp of approval. The committee reviews all blood pressure monitors, including the stations you see at grocery stores and pharmacies. So, while not everything you see on the site is going to fit your needs or budget, it’s a quick way to find a product you can trust.

Of course, even the best blood pressure monitors aren’t always going to be perfect. Manufacturing errors, wear and tear, battery depletion — there are plenty of issues that can cause inaccurate readings. That’s why it’s important to test your device against other monitors on a regular basis.

Most monitors you find in a drugstore or online are fine, Dr. Laffin says. But it doesn’t hurt to take it to your doctor’s office and check yours against the office monitor.

“If the systolic blood pressure (the top number) on your cuff is within 10 points of the monitor, then it’s generally accurate,” he says.

Most home blood pressure machines last for about two or three years. After that, check it at your healthcare provider’s office annually to make sure it’s still accurate.

Three is better than one

There’s one extra feature you might consider seeking out to help boost a monitor’s accuracy: Taking three measurements automatically.

Some monitors do this each time you check your blood pressure. They take a first reading; wait 30 to 60 seconds and take a second reading; then wait 30 to 60 more seconds and take a final measurement.

“This is helpful because it averages your three readings, which probably more closely reflects your actual blood pressure than the first number alone,” Dr. Laffin explains.

A no-pressure purchase

If you find yourself in a situation where you need to regularly monitor your blood pressure, the last thing you need is uncertainty — about the product you’re buying, your testing procedure or the readings you’re getting. You can now consider yourself armed (get it?) with all the basic information you need.

If any other questions come up, don’t be shy about checking in with your healthcare provider. If they’re asking you to check your blood pressure regularly, they’re going to be just as invested as you are in making sure it’s done right!