Oximetry

An approximation of your blood’s oxygen content can be made with a small plastic finger clip that measures the absorption of light through your fingernail. Oxygenated blood is much redder than non-oxygenated blood, and this device can instantly determine the percentage of oxygen saturation in your blood stream (it also determines your pulse.)  The test takes only seconds and is painless and harmless.

This test may also be done while you are walking, to determine if your oxygen levels drop significantly with exercise.