Oxygen saturation is a noninvasive way to measure how much oxygen is moving through the bloodstream. This test is performed by a health care professional or by a person at home.
According to the ninth edition of Mosby's Diagnostic and Laboratory Test Reference, the normal level of oxygen saturation is equal to or greater than 95 per cent.
The oxygen saturation test is performed for many reasons, including to assess a person's response to medications and to ensure a person's current oxygen level is adequate. This test is also performed during stress testing and sleep studies.
Testing for an oxygen saturation level involves placing a pulse oximeter probe on a person's ear or fingertip and generally takes few seconds.
People with certain lung conditions, like chronic obstructive pulmonary disease (COPD), may have a lower "normal" oxygen saturation level. The oxygen saturation goal, according to the American Thoracic Society, is to maintain an oxygen saturation level greater than 90 per cent.
According to the ninth edition of Mosby's Diagnostic and Laboratory Test Reference, a possible critical oxygen saturation level is equal to or less than 75 per cent.