Researchers report that a popular smartphone app that checks blood pressure is inaccurate. The app misses four out of five high blood pressure readings, according to the report.
The app is called Instant Blood Pressure, and it promises to estimate blood pressure if the smartphone user places their index finger on the phone camera and their phone on their left chest.
The app came back with normal blood pressure for nearly 80 percent of people who struggle with clinically high blood pressure (140/90), the study found. Researchers cautioned that people who use the app to routinely track their blood pressure will likely be told more often than not that they’re fine, even if they’re not.
The $4.99 app has been removed from Google Play and the iPhone App Store, but copycat apps remain in the marketplace.
The app was a bestseller on iPhones for 156 days before it was removed from the store. Each day, at least 950 copies were sold. This is more copies than Angry Birds on some days.
Left untreated, high blood pressure is a precursor to stroke, heart disease, kidney damage, and other health challenges. The researchers set out with the hope of validating the app, given the known health issues that can come up with untreated high blood pressure.
They recruited 85 adults for the study. Researchers measured participants’ blood pressure twice using the app and twice using the standard blood pressure cuff.
On average, the blood pressure app was 12 points off for systolic blood pressure and 10 points off for diastolic blood pressure. Systolic reflects the pressure when the heart beats while diastolic reflects pressure between heartbeats.
Inaccurate blood pressure readings matter. It’s not okay to be off by 5 or 7 points. That’s the difference between recognizing your blood pressure is not improving and allowing the problem to persist, which can lead to further health complications.
The U.S. Food and Drug Administration issued guidelines to regulate mobile medical apps in February 2015, within months of Instant Blood Pressure’s release.
The FDA plans to regulate any app meant to use a smartphone as a medical device.