A recent review of cuffless BP meters has called for consensus on standards for testing cuffless devices for accuracy.¹⁶

These derive BP values by combining data from signals such as the speed of the pulse travelling along an artery, the duration of the pulse, a pressure sensor partially compressing a radial artery, or by vascular unloading – the extent to which external pressure (eg to a finger) needs to be modified to keep the arterial blood volume constant.

Devices can do this by using optical data with green light reflecting from the skin, force sensors, and electrocardiograph (ECG) readings. As BP is not measured directly but is calculated from the various data sets, cuffless BP monitors need to be calibrated regularly against a cuffed device.

With the technology rapidly evolving to measure absolute BP or changes in BP, and with increasing uptake, the review authors have called for uniform standards for proper validation of these devices, especially in ambulatory settings. This should also include validation in pregnancy, in people with arrythmias and those on medication such as beta-blockers, as well as for different heart rates, skin tones, and wrist sizes.

The BIHS does not yet list devices for measuring pulse wave velocity, arterial stiffness or central blood pressure monitoring due to the lack of internationally agreed validation criteria for these types of machines.¹¹