Oxygen Saturation

Pulse oximetry.

To evaluate how well the lungs are providing oxygen to the blood during rest, exercise, or a medical procedure.

Oxygen concentration determines the color of the blood, which in turn determines the refraction of light that passes through the skin. A device called an oximeter analyzes the refraction to determine the blood's oxygen saturation: Well-oxygenated blood is bright red, while blood carrying less oxygen is darker.

None.

• The probe is attached to your finger, earlobe, or toe.
• The probe emits a light signal, which passes through the finger, earlobe, or toe.
• Because some people have poor blood oxygenation only during activity, the test may be performed while you are exercising on a stationary bicycle or treadmill.

• The clip is removed, and you are free to return to previous activities.
• After exercise, cool down gradually by walking or pedaling slowly for a few minutes. Your pulse and blood pressure may be monitored during this time until they return to normal.

• Poor circulation in the fingers, toes, or earlobe.
• Bright external light.
• Smoking can affect blood oxygenation.

It is considered abnormal if oxygen saturation declines by more than 5% during exercise or sleep. Normal resting oxygen saturation is usually greater than 90%.

It's noninvasive, quick, and simple.

It has limited diagnostic value because it evaluates only oxygen saturation.

Measurement of oxygen saturation will help your doctor evaluate the severity of your disease, and will determine if you need supplemental oxygen.