Patient education: How to use a pulse oximeter (The Basics)

What is a pulse oximeter? — A pulse oximeter, or "pulse ox," is a small device that measures the amount of oxygen in the blood. It is often placed on a fingertip, but can also be attached to a toe, ear, or nose.

A pulse oximeter can help your doctor check your oxygen levels. Your doctor might suggest using one if you are short of breath, have a condition that affects your breathing, or use oxygen. For example, you might need to use a pulse oximeter if you:

●Have chronic obstructive pulmonary disease ("COPD"), asthma, or other lung diseases

●Have an illness like heart disease or stroke

●Have pneumonia, the flu, or COVID-19

●Take medicines like opioids, which can affect your breathing

In some situations, your doctor or nurse might ask you to use a pulse oximeter at home.

How does a pulse oximeter work? — The pulse oximeter attaches like a clip to your fingertip. The clip shines a light, which might make your fingertip look red. A tiny computer in the clip can read your oxygen level by the color of the light that shines through the other side.

Your doctor's office or hospital might use a disposable pulse oximeter. This can look more like a flexible tape with a cord attached to it. The tape has the light sensor in it and works the same way as the clip style.

How do I use a pulse oximeter? — Sit in a comfortable position. Place the clip on your fingertip, and leave it in place for a few minutes. The light from the clip will record your pulse rate and the amount of oxygen in your blood. This is called the "oxygen saturation."

Your results will help the doctor decide if you need extra oxygen. Most healthy people have an oxygen saturation level between 92 and 100 percent. Your normal level might be higher or lower, depending on your health.

In some cases, your doctor will tell you to use extra oxygen, take medicines, or do breathing exercises if your levels are low.

What else should I know? — Sometimes, a pulse oximeter might have trouble measuring the amount of oxygen in your blood.

Examples of things that can affect your results include:

●Poor circulation

●Low skin temperature

●Thickened skin

●Dark skin tone

●Dark nail polish or artificial nails

●Arthritis of the fingers or hands

●Movement

●Heavy smoking

Sometimes, it's possible to avoid these problems by using a different body part instead of a fingertip. If needed, your doctor or nurse can do other tests to check your oxygen level.

When should I call the doctor? — Call your doctor for advice if:

●You are having so much trouble breathing that you can only say 1 or 2 words at a time.

●You need to sit upright at all times to be able to breathe or cannot lie down.

●You have trouble breathing when talking or sitting still.

●Your oxygen level is lower than normal for you.

More on this topic

Patient education: Oxygen therapy at home (The Basics)
Patient education: Chronic obstructive pulmonary disease (COPD) (The Basics)
Patient education: Asthma in adults (The Basics)
Patient education: Asthma in children (The Basics)
Patient education: Cystic fibrosis (The Basics)
Patient education: Pneumonia in adults (The Basics)
Patient education: Pneumonia in children (The Basics)
Patient education: Flu (The Basics)
Patient education: COVID-19 overview (The Basics)

Patient education: Chronic obstructive pulmonary disease (COPD) (Beyond the Basics)
Patient education: Pneumonia in adults (Beyond the Basics)
Patient education: Influenza symptoms and treatment (Beyond the Basics)