If you take a coronavirus test, what should your oxygen level be?

Oxygen levels - COVID-19
Photo via Juhan Sonin/Flickr (CC BY 2.0)

Prior to COVID-19, many people spent their lives without giving their oxygen levels a second thought. Thanks to the ongoing pandemic and COVID-19’s known effects on our lungs, however, many people have begun tracking their levels. The average person doesn’t know much about this process, which is prompting people to wonder what a healthy person’s oxygen levels should be and if they should be concerned about their own.

Your blood oxygen level measures how much oxygen is circulating in your red blood cells. It can be tested with a small device that clips onto your finger—you may have seen one the last time you visited the doctor. This device is called a pulse oximeter. It provides results in a percentage, and a typical oxygen level should fall between 95 and 100%. If your readings fall much below this, you should contact your health provider.

“If oxygen levels are below 88%, that is a cause for concern,” critical care specialist Christian Bime of Banner University Medical Center Tucson said. 

COVID-19 has a severe impact on many people’s oxygen levels. It is not necessary to check your levels if you’ve contracted the coronavirus, but it can help to show how your oxygen intake has been impacted. 

If you’d prefer another method to check that your levels are where they should be, there are a few options. A typical FDA-approved oximeter costs between $15-$30, but you may already own a device capable of tracking your oxygen levels. Several high-end fitness devices—including the Apple Watch Series 6, some Fitbit and Garmin products, and the Wellue Continuous Ring Oximeter—are capable of tracking your levels. These have not been approved by the FDA, however, so any results should be considered with a certain amount of skepticism. 

If you are concerned about your oxygen levels, you can purchase an oximeter for at-home use. People with lung and heart conditions often use them to keep an eye on their day-to-day oxygen levels. It cannot be used to diagnose cases of COVID-19, however. If you are displaying symptoms or have recently come in contact with someone known to have the virus, you should self-isolate and get tested immediately.

If you know you’ve contracted COVID-19, an oximeter or similar tool can be useful in keeping an eye on your oxygen. Common signs of low oxygen levels include shortness of breath, quicker-than-usual breathing, and feeling too sick to participate in typical daily activities. 

Not everyone who develops COVID-19 will experience lowered oxygen levels, but many do. During the pandemic, doctors have noticed a trend they’re calling “happy hypoxia.” This phenomenon sees patients with COVID-19 feeling healthy but experiencing low oxygen levels. This can be dangerous, as patients feel reasonably healthy and, therefore, don’t seek medical attention. An at-home oximeter could help with these somewhat rare occurrences. 

It is notable that oximeters can give falsely low readings to people with poor circulation to their extremities. Fake nails and some dark colored nail polishes can also alter readings, prompting doctors to recommend that people test at least one finger from each hand to ensure accurate readings. 

The people at most risk of developing low oxygen levels are those with preexisting conditions like heart disease, lung disease, and obesity or those who are active smokers.

Sources: Banner Health, Minnesota Department of Health, Houston Methodist Health

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