Night oximetry consists of the all-night continuous measurement of arterial oxygen saturation.  This is done non-invasively with the pulse oximetry method. (SpO2).

Drops in saturation values recorded during the night are considered one of the most important parameters in identifying sleep apnea. But the value of night oximetry extends beyond sleep apnea diagnosis. It can also be used for example in patients with COPD to determine the need for supplemental oxygen at night.