Pulse oximetry device, system and method

A method of taking pulse oximetry measurements, the method comprising:

• providing a first, reference pulse-oximeter adapted to measure reference Oxygen saturation (SpO2) values on a basis of a first predetermined pulse oximetry parameter calculated from a first, reference Photoplethysmography (PPG) signal measured by the reference pulse-oximeter on a non-wrist body portion sufficiently perfused with arterial blood of each of one or more test subjects;
• using said first, reference pulse-oximeter, measuring reference SpO2 values for multiple measurements carried out on the non-wrist body portion of each of the one or more test subjects;
• from the reference SpO2 values, obtaining a calibration relationship that expresses SpO2 as a function of the first predetermined pulse oximetry parameter;
• providing a second, bracelet-type pulse oximetry device adapted to acquire SpO2 a second PPG signal on a wrist of a target subject, wherein the device is adapted to calculate therefrom a second predetermined pulse oximetry parameter;
• using the second, bracelet-type pulse oximetry device, performing one or more acquisitions of the second PPG signal on the wrist of the target subject;
• calculating from the one or more acquisitions of the second PPG signal one or more corresponding values of the second predetermined pulse oximetry parameter;
• converting said one or more corresponding values of the second predetermined pulse oximetry parameter into measured SpO2 values using said calibration relationship.