The future of blood pressure monitoring: Cuffless devices

Many devices that measure blood pressure without an inflatable arm cuff are in development, including a wristband recently cleared by the FDA for over-the-counter sale. It relies on a light-based sensor to detect changes in the amount of blood flowing through the vessels of the inner wrist, a technique known as photoplethysmography. But the devices have to be periodically calibrated, and as yet, there are no standards to validate the accuracy of cuffless devices.