Hypoxia is a state in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis; this can result from inadequate oxygen delivery to the tissues either due to low blood supply or low oxygen content in the blood (hypoxemia).

Healthy pulse oximeter values often range from 95% to 100%. Values under 90% are considered low. Often, hypoxemia treatment involves receiving extra oxygen.

Pulse oximetry is a test used to measure the oxygen level (oxygen saturation) of the blood. It is an easy, painless measure of how well oxygen is being sent to parts of your body furthest from your heart, such as the arms and legs.