Pulse Oxygen Saturation (Arterial)

This test estimates the percentage of oxygen carried by your red blood cells in arterial blood using a pulse oximeter. A small sensor placed on a finger, toe, or ear shines light through your tissue and analyzes how much is absorbed to estimate how much hemoglobin is bound to oxygen.

It provides a quick, noninvasive snapshot of how well your lungs are transferring oxygen into your bloodstream and how effectively your heart and circulation are delivering it to your body. Clinicians use it in clinics, hospitals, and at home to monitor oxygenation in real time.

Your oxygen saturation helps your care team assess breathing problems, guide oxygen therapy, and track response to treatment. It is commonly checked if you have symptoms like shortness of breath, chest discomfort, or changes in mental alertness, and during procedures that may affect breathing such as sedation or anesthesia.

It is also useful in monitoring chronic lung and heart conditions, infections that affect the lungs, and recovery after surgery. Knowing your saturation can alert clinicians to problems early so they can adjust oxygen, medications, or other support to keep you safe.

Interpretation depends on your overall health, symptoms, and the clinical setting. A reading that is lower than expected for you may suggest that your lungs are not moving enough oxygen into your blood or that blood flow to the sensor site is reduced. If results are unexpected, your clinician may repeat the test, check the sensor placement, warm the hand, or compare with another site.

If low or changing results persist, your clinician may order additional tests, such as an arterial blood gas or imaging, and consider treatments like supplemental oxygen or therapies targeted to the underlying cause. Seek urgent care if you have severe shortness of breath, chest pain, confusion, or bluish discoloration of lips or fingers.