Americans continue to rack up unfortunately high scores on common health problems. According to the CDC, approximately 75 million adults in the U.S have hypertension (high blood pressure). Another 75 million have prehypertension: blood pressure scores that are above normal but not quite in the hypertension range. Those numbers account for 2 of every 3 American adults. Blood pressure cuff devices remain the standard mode for measuring blood pressure, but the cuffs are awkward for many people to use. Smartphone apps that read data from sensors may be the new standard in time, but that’s not yet the case. Alfred Poor wrote about Valencell’s optical blood pressure sensor, a device he saw and tried at CES 2017.

A team of Michigan State University scientist recently unveiled a work-in-progress sensor-equipped smartphone case and a mobile app to read blood pressure. A study reported in Science and Translational Medicine details the MSU success. The case has an optical sensor on top of a force sensor. Preparing for their testing regimen, the MSU team validated the transverse palmar arch artery at the fingertip. Taking a reading from a fingertip is more comfortable and less awkward than a cuff wrapped around the upper arm or wrist. Users start the smartphone app, hold the phone level with their heart, and press their finger on the optical sensor. The pressure sensor indicates the applied finger pressure on the screen so users know when they are pressing hard enough; they have to increase the pressure over the course of a reading. According to the MSU scientists, 90% of the users were able to hold the case with the right amount of force after just one or two practice runs. The smartphone case-based blood measurement setup was as accurate as finger cuff devices, the scientists report, but not quite as accurate as standard cuff devices.

The MSU test numbers support the validity of the identified finger artery as a measurement location. Finding that users can learn how to get a reading with the dual-sensor device with minimal training crossed another big hurdle. The next steps include further development and testing to push for standard-level accuracy and reliability. The MSU final product could represent a significant step forward in helping Americans take their own fast, accurate, and convenient blood pressure readings.