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Pulse Oximetry (Pulse Ox)

Reviewed by: Larissa Hirsch, MD

What Is Pulse Oximetry?

Pulse oximetry (often called pulse ox) is a painless test to measure how much oxygen is in the blood.

Why Is Pulse Oximetry Done?

Doctors may order pulse oximetry to see if there is enough oxygen in the blood. Oxygen levels may be low with lung infections, asthma, heart problems, allergic reactions, after anesthesia, and with other medical conditions.

How Should We Prepare for Pulse Oximetry?

If your child has nail polish on, the polish may need to be removed to allow the pulse ox to accurately measure the oxygen level.

What Happens During Pulse Oximetry?

During pulse oximetry, a small clip or bandage is put on a child's finger, toe, foot, or earlobe. This is called a sensor, and uses light to measure how much oxygen is in the blood.

Sometimes pulse ox is done once to get a single oxygen reading, and sometimes the sensor is left on for continuous monitoring of oxygen levels. If the sensor isn't put on well, it can affect the reading and make the oxygen level look lower than it actually is.

Can I Stay With My Child During Pulse Oximetry?

Parents can stay while their child wears the pulse ox sensor.

How Long Does Pulse Oximetry Take?

It usually takes a few seconds for the sensor to get the reading it needs. If your child is calm and staying still, it can help the pulse ox be more accurate.

When Are the Results Ready?

Pulse ox results are available immediately.

Are There Any Risks From Pulse Oximetry?

Pulse oximetry is a safe test. Occasionally, the sensor can cause skin irritation.

If you have questions about the pulse ox, speak with the doctor or another health professional on your child's care team.

Reviewed by: Larissa Hirsch, MD
Date reviewed: March 2018