Abstract: There is provided a method of taking pulse oximetry measurements, the method comprising: providing a calibration pulse-oximeter adapted to estimate one or more first, reference SpO2 values from a first, reference PPG signal measured by the pulse-oximeter on a first, reference area of the human body: and, using the same or a different calibration pulse-oximeter, estimating one or more second SpO2 values from a second PPG signal measured by said same or different calibration pulse-oximeter on a second, target area of the human body. At this point, a calibration parameter or calibration function is calculated on the basis of the one or more first, reference SpO2 values and the second SpO2 values. Then, using a measurement pulse-oximeter, a plurality of third SpO2 values is measured from the second PPG signal on the second, target area of the human body and the resulting values are calibrated using said calibration parameter or function.

Abstract: A method of measuring blood oxygenation consists of measuring Sp02 on one or more test subjects using a first, reference pulse oximetry device (100), such as a medical-grade pulse-oximeter of the kind that employs, for example, a finger-tip clip-type probe. This can be done on each patient over relatively short time periods. Then, the Sp02 is monitored on a target subject across a relatively longer time period using a second, wearable pulse oximetry device (10) that can be worn non-intrusively by the target use, for example in the form of a bracelet. The Sp02 measured using the wearable pulse oximetry device (10), can be measured based on calibration measurements performed using the first, reference pulse oximetry device (100). In this way, the measurements produced by the wearable pulse oximetry device (10) are calibrated using a medical-grade pulse-oximeter (100).