The small medical device is gaining attention for its ability for its purported ability to monitor coronavirus symptoms. But do you really need a pulse oximeter on hand?

By Korin Miller
May 06, 2020
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As the coronavirus continues to spread, so does talk about a small medical device that might be able to alert patients to seek helper sooner. Reminiscent of a clothespin in shape and size, the pulse oximeter gently clips onto your finger and, within seconds, measures your heart rate and blood oxygen level, which can both be impacted in COVID-19 patients.

If this sounds vaguely familiar, that's because you've likely experienced the device first-hand in a doctor's office or, at bare minimum, have seen it on an episode of Grey's.

Despite their newfound popularity, pulse oximeters are not part (at least not yet) of the official COVID-19 prevention and treatment guidelines established by major health organizations. Still, some doctors believe the little gadget can be a crucial player amid the pandemic, helping people, especially those who are immunocompromised and with preexisting lung conditions (due to their increased risk in contracting the virus), to monitor their levels without leaving their house (after all, most states are still emphasizing the importance of staying at home). Remember: the coronavirus can wreak havoc on your lungs, leading to breathlessness and lowered blood oxygen level.

Here's what you need to know.

What is a pulse oximeter and how does it work? 

A pulse oximeter (a.k.a. pulse ox) is an electronic device that measures your heart rate and the saturation or amount of oxygen in your red blood cells, according to the American Lung Association (ALA). While it technically can be attached to other parts of your body (i.e. nose, ears, toes), a pulse oximeter is typically placed on one of your fingers. The tiny device gently clamps down on your finger and measures your blood oxygen level by shining light through your fingertip. It's targeting hemoglobin, a protein in your red blood cells that carries oxygen from your lungs to the rest of your body. Depending on how much oxygen it's carrying, hemoglobin absorbs different amounts and wavelengths of light. So, the amount of light absorbed by your blood signals your blood oxygen level to the pulse, according to the World Health Organization (WHO).

While some research has found that the accuracy of these readings can vary depending on the finger used, most medical professionals put a pulse oximeter on a patient's index finger. You do want to avoid dark nail polish and long or fake nails, as these factors—as well as cold hands—can impact the accuracy of the results, says Osita Onugha, M.D., chief of robotic thoracic surgery and director of the Surgical Innovation Lab at John Wayne Cancer Institute at Providence Saint John's Health Center in Santa Monica, California.

So what should your pulse oximeter reading be, ideally? Your blood oxygen saturation should be anywhere between 95-100 percent, according to the WHO. Most healthy people, however, will get a reading between 95-98 percent, says Dr. Onugha. And if your readout dips below 93 percent, you should call your doctor, especially if your level has been higher in the past, adds David Cennimo, M.D., assistant professor of medicine at Rutgers New Jersey Medical School. This could mean that you're potentially hypoxic, in which your body is deprived of oxygen, according to the WHO. However, a 1 to 2 percent variation from reading to reading is normal, adds Dr. Cennimo.

"In some ways, this is like having a thermometer," he says. "[A pulse oximeter] can be useful, but I hope that it will not make someone crazy to obsess over numbers. On the other hand, if someone feels short of breath or has other respiratory symptoms that are causing them concern, they should seek care even if their pulse ox is 'normal.'" (Related: Is This Coronavirus Breathing Technique Legit?)

And, during the coronavirus pandemic, it's these respiratory concerns that have people on high-alert for any change in lung function or health right now.

Can you use a pulse ox to detect coronavirus?

Not exactly.

COVID-19 can cause an inflammatory reaction in the lungs, lung complications such as pneumonia, and/or tiny, microscopic blood clots in the lungs. (Which, btw, is one reason why vaping is believed to increase your coronavirus risk.) When someone develops a lung disease or lung issue(s), their body may have trouble transferring oxygen from their alveoli (little sacs in the lung at the end of your bronchial tubes) to their blood cells, says Dr. Cennimo. And this is something doctors are finding in COVID-19 patients, he adds. (Psst...some coronavirus patients might also experience a rash.)

Doctors are also noticing a worrisome trend known as "silent hypoxia" amongst coronavirus patients, where their oxygen saturation levels get extremely low, but they don't have breathlessness, says Dr. Cennimo. "So, there have been suggestions that more monitoring could identify the drop in oxygen saturation—and trigger giving oxygen—sooner," he explains.

Meanwhile, there's also the argument that regular monitoring with a pulse oximeter may be helpful to screen essential workers to signal if they've contracted the virus and need to go into isolation. But Dr. Onugha isn't convinced that will be helpful. "With COVID-19, you're more likely to present with fever first, then a cough, then difficulty breathing, if it gets to that point. A lower oxygen saturation level is unlikely to be your first symptom," he says. (Related: The Most Common Coronavirus Symptoms to Look Out for, According to Experts)

So, should you buy a pulse oximeter? 

The theory is that regularly and properly using a pulse oximeter could allow patients with and without COVID-19 to keep track of their oxygen saturation levels. But before you run out to buy one, know that doctors are divided on whether or not they're really a pandemic necessity (such as, say, face masks).

"I think it is a good idea for patients with COVID-19 who are isolating at home, as long as they know what to do with the information—what oxygen level is too low, and what to do if that happens," says Richard Watkins, M.D., an infectious disease physician in Akron, Ohio, and an associate professor of internal medicine at Northeast Ohio Medical University. (Don't panic and call your doctor.)

He also thinks a pulse ox can be valuable for people who have a suspected (read: not confirmed) case of COVID-19: "I have wondered about people who have died at home—especially young people—if having a pulse oximeter could have alerted them or their family that they were in trouble." (Related: Exactly What to Do If You Live with Someone Who Has Coronavirus)

But not everyone thinks its a necessity. Dr. Onugha and Dr. Cennimo both agree that the device likely isn't needed for the general population. "If you have a pre-existing condition like asthma or COPD, it may be helpful for you to know what your oxygen saturation levels are," adds Dr. Onugha. "And, if you're diagnosed with COVID-19, it may be helpful [to monitor your condition], but, in general, I don't think it's beneficial for everyone."

Plus, there are currently no official recommendations from major medical associations such as the Centers for Disease Control and Prevention (CDC), WHO, and American Medical Association (AMA) about using a pulse oximeter when it comes to COVID-19. What's more, the ALA recently issued a press release, warning that a pulse oximeter is "not a substitute for talking to a healthcare provider" and that "most individuals do not need to have a pulse oximeter in their home." (Related: What to Do If You Think You Have the Coronavirus)

Still, if you do want to buy one for coronavirus-related reasons or otherwise—they are affordable and these at-home versions are accessible—whatever pulse oximeter you can find at a local drugstore or online should suffice, says Dr. Onugha. "They're all fairly accurate, for the most part," he says. Try ChoiceMMEd Pulse Oximeter (Buy It, $35, or NuvoMed Pulse Oximeter (Buy It, $60, Head's up that many pulse oximeters are currently sold out, so it might take a little searching to find an available gadget. (If you want to be super thorough, you can check the Food and Drug Administration's Premarket Notification Database and search for "oximeter" to get a list of the devices that are recognized by the FDA.)

The information in this story is accurate as of press time. As updates about coronavirus COVID-19 continue to evolve, it's possible that some information and recommendations in this story have changed since initial publication. We encourage you to check in regularly with resources such as the CDC, the WHO, and your local public health department for the most up-to-date data and recommendations.


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