Measure Blood Oxygen Level (SpO2)

Pulse oximetry can be used to determine the arterial oxygen saturation, or SpO2 for short. The SpO2 value indicates what percentage of the total haemoglobin in the blood is saturated with oxygen. The level of oxygen saturation allows to draw conclusions about the efficiency of the lungs.

In general, haemoglobin in arterial blood is 97-100% saturated. Only under the highest loads or extreme circumstances does it reach values below 95%, such as mountaineering at extreme heights or clinical emergencies.

More information about blood oxygen saturation

How does our sensor technology measure the oxygen saturation of the blood?

Different from the finger clips commonly used in hospitals, the ear sensor does not measure transmissively, but reflexively in the auditory canal. The SpO2 value can be derived from the alternating current and direct current of the red/infrared PPG raw signals. The agreement with the reference pulse oximeter (clinical finger clip) is very good, even at low SpO2 levels.

SpO2 measurement using an ear sensor in comparison to the reference (finger clip) during a desaturation measurement.


For all important parameters, extensive studies are carried out in cooperation with renowned partners and are statistically evaluated. Medically approved standard measuring instruments are used as a reference.

Further clinical studies to validate the blood oxygen saturation are already being planned.

Study ManagementReferenceNumber of SubjectsData in HoursMean ErrorStandard Deviation
Cosinuss° GmbHFinger pulse oximeter72+ 0.2 %± 1.7 %