Should You Get a Pulse Oximeter to Measure Blood Oxygen Levels?

First, it was hand sanitizer and disinfectant wipes. The latest item flying off the shelves in response to the 2019 novel coronavirus? The pulse oximeter, a medical device that clips to your finger to measure the amount of oxygen in your blood.

But is this something you actually need in your medicine cabinet? The answer is, it depends, says pulmonologist Wayne Tsuang, MD.

He breaks down what a pulse oximeter — or “pulse ox”— can tell you, and whether you might want to get one.

Coronavirus and blood oxygen levels

Oxygen is the fuel your body needs to function. Insufficient oxygen in the blood can interfere with the function of the heart and brain.

Doctors have discovered that some people with COVID-19 have dangerously low blood oxygen — even though they don’t feel short of breath.

“We’re seeing reports of ‘silent hypoxia,’ or low oxygen levels in some patients without severe symptoms,” Dr. Tsuang says.

In response to those reports, people have started buying pulse oximeters to keep tabs on their oxygen levels if they get sick. 

Should you invest in a pulse ox?

• If you have been diagnosed with COVID-19: If you’ve caught the virus and are recovering at home, a pulse oximeter can give you some important data points to share with your doctor. If your oxygen levels fall too low, your doctor may want you to come in for more testing or hospital care, Dr. Tsuang says.
• If you don’t have COVID-19 but have other medical conditions: Buying a pulse oximeter might be a good idea if you have underlying illnesses, such as diabetes, heart disease or lung diseases, Dr. Tsuang says. “In those cases, it’s helpful to do at-home monitoring so you can gather more information to give to your doctor.”
• If you’re healthy: If you’re otherwise healthy and have no symptoms of COVID-19, a pulse oximeter is not a must-have item for your medicine cabinet, Dr. Tsuang says. And just like the Great Toilet Paper Craze of March 2020, there could be shortages if everyone rushes out to buy a pulse oximeter.  “We want to make sure people with lung diseases who need the devices for home monitoring still have the opportunity to get them,” he adds.

What to look for in pulse oximeters

Pulse oximeters come in a wide variety of styles and price points. Dr. Tsuang recommends buying one from a reputable store or website, such as a pharmacy or medical device supplier.  

Some smart watches and fitness trackers also measure blood oxygen saturation. But they might not be as reliable as medical devices, he cautions, so take the numbers with a grain of salt.

Blood oxygen: How low is too low?

What should you be looking for? A healthy oxygen saturation is typically above 90%. If your number dips below 90%, Dr. Tsuang says, call your doctor for advice.

Remember, too, that low oxygen is just one sign of COVID-19. Even if you have a healthy blood oxygen level, don’t ignore other possible symptoms, like cough or shortness of breath.  

“The pulse ox is just one piece of data,” says Dr. Tsuang. “If you have any concerns or questions, your doctor will look at all of your symptoms and vital signs to get the whole picture.”