Yes, you can and you should use a pulse oximeter to check for COVID-19 symptoms, according to Doctors Christy Reisinger and Richard Levitan. Both doctors treat COVID-19 patients. They both report that low blood oxygen is a seen in most if not all patients infected with COVID-19.
Dr. Levitan sees many patients with COVID-19 and severe hypoxemia (low blood oxygen). He reports that these patients have dangerously low oxygen, but in general do not have low blood oxygen symptoms.
Normally a person with low oxygen is dizzy and out of breath. He reports that many COVID-19 patients have severe hypoxemia but are unaware of their condition. They are not dizzy or out of breath.
Learn more about Dr. Levitan’s advice in our article (opens in a new page): Should Seniors Go to the Hospital with COVID-19 Symptoms?
COVID-19 Presents with Silent Hypoxia
Dr. Levitan called this extreme but symptom-less blood oxygen condition the “silent hypoxia.” He suggests that people concerned about catching COVID-19 early use a pulse oximeter as a safety net to catch a hypoxemia condition.
Dr. Reisinger reports that she sees COVID-19 patients presenting with hypoxemia and low-grade fever. She suggests that people in higher-risk categories check their oxygen levels using pulse oximeters at home.
Dr. Reisinger says that when people have a combination of a fever and low oxygen that they should seek medical help.
What is Pulse Oximetry and How Does it Work?
A pulse oximeter is a non-invasive and painless blood oxygen meter. It attaches to a peripheral body part such as a finger, toe, ear or wrist. It shines a light onto blood inside the body. Changes in the blood’s color indicate oxygen level changes.
The pulse oximeter then displays two values for the user. These are the blood oxygen level and the heart rate.
What Do Pulse Oximeter Values Indicate?
A pulse oximeter displays two values:
- the user’s blood oxygen level,
- the user’s heart rate in beats per minute (BPM)
You wear a pulse oximeter to check if:
- your blood oxygen is too low (hypoxemia)
- your pulse rate is too low (bradycardia)
- your pulse rate is too high (tachycardia)
A healthy blood oxygen saturation level is 95% to 100%. The oximeter warns the user of hypoxemia (low blood oxygen) when it displays an oxygen level of less than 95%.
The heart rate monitor displays the user’s heart rate in beats per minute (BPM). Whether this value represents a healthy or an unhealthy state is relative to the user’s fitness and health conditions.
How to Read a Pulse Oximeter Oxygen Level
To read the blood oxygen percentage:
- A healthy reading is 95% to 98%.
- A reading of less than 95% can indicate “cellular profusion compromise” (you are cells are starved for oxygen).
- A reading of less than 90% can indicate “severe cellular profusion compromise.” A reading under 90% represents an immediate and dangerous condition. The blood oxygen level is so low that the body will not be able to sustain itself. Severe hypoxemia (low blood oxygen) is a deadly condition.
How to Read a Pulse Oximeter Heart Rate
Pulse oximeters display the user’s heart rate in beats per minute (BPM).
A “normal” heart rate depends on the user’s fitness level. A healthy heart rate for one person is an unhealthy heart rate for another person.
You can discuss your ideal heart rates with your doctor.
These are the heart rate ranges and what they mean for elite athletes and then for normal people.
- A heart rate of 40-60 beats per minute (BPM) is normal for a well-trained athlete
- A heart rate of 40-60 BPM for a non-athlete is bradycardia. Bradycardia often includes dizziness and shortness of breath.
- A normal resting heartbeat is 60-100 BPM.
Why Would My Pulse Ox Be Low?
A low pulse oximeter reading means that the blood is not carrying enough oxygen. This is a dangerous condition called hypoxemia.
The Mayo Clinic lists 15 possible hypoxemia causes. These include sleep apnea, pneumonia, and COPD. See the next section to read the Mayo Clinic and the WHO’s medical condition lists. People with those conditions should wear a blood oxygen meter (pulse oximeter) at home.
Who Uses Pulse Oximeters at Home?
Dr. Richard Levitan and Dr. Christy Reisinger suggest that people use pulse oximeters to screen themselves for COVID-19.
Dr. Levitan reports that low blood oxygen level can be a sign of COVID-19 infection. Dr. Reisinger reports that low blood oxygen with even a mild temperature rise is a sign of COVID-19 infection.
Outside of the pandemic, medical authorities suggest that certain lung and heart patients use pulse oximeters at home.
The Mayo Clinic says people with these conditions below should use a pulse oximeter:
- ARDS(Acute respiratory distress syndrome)
- Congenital heart defects in children
- Congenital heart disease in adults
- COPD(chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
- Interstitial lung disease
- Medications, such as certain narcotics and anesthetics, that depress breathing
- Pneumothorax(collapsed lung)
- Pulmonary edema(excess fluid in the lungs)
- Pulmonary embolism(blood clot in an artery in the lung)
- Pulmonary fibrosis(scarred and damaged lungs)
- Sleep apnea
The World Health Organization instructs nurses to test for hypoxemia in people who have ingested:
- volatile agents
- muscle relaxants
Why Does My Pulse Ox Need to Be Measured?
A person must have oxygen in the blood or they will die. The human body requires a minimum of 95% oxygen saturation. Less than 95% is somewhere between dangerous and very dangerous.
Oxygen deprivation kills tissues that support life. When your pulse oximeter displays a value less than 95%, you should seek medical help.
Why are Pulse Oximeters Sold Out?
As I write this answer in May of 2020, we are still in the COVID-19 quarantine.
As soon as people learned that hypoxemia indicated a possible infection, they bought pulse oximeters by the thousands.
For example, a store called Health Product for You sells forty-four pulse oximeter models. Their entire supply is out of stock.
Where are Pulse Oximeters Available?
Some stores do have quality oximeters. I am maintaining a list of good pulse oximeters that are in stock.
You can view the list here (opens in a new window): Recommended (In Stock!) Pulse Oximeters for COVID-19 and Sleep Apnea Monitoring.
Why Do Pulse Oximeter Readings Vary?
According to the World Health Organization, pulse oximeter results vary for a number of reasons.
You might get varying results because:
- the probe is not positioned well around the target ear or finger area
- the probe is too loose or too tight
- the target area is too large for the probe clamp (using a finger probe on a big toe)
- the target area is too small (using an adult probe on a child)
- an ear probe is placed on a hypovolaemic ear (it has a fluid imbalance)
- cold exposure constricts the target
- nail polish interferes color changes the color the probe sees
- a bright light interferes with the probe’s light
- the patient moves
- poor perfusion (circulation)
- carbon monoxide poisoning causes an oxygen miscalculation
- the probe is poorly calibrated to the target pigment
- a tattoo interferes with the color the probe sees
- the battery is not charged
- the probe is dirty
Where Can Pulse Oximetry Be Taken?
Most medical-use pulse oximeters take readings from the index finger.
Others take readings from the ear, wrist, or toes.
Sleep apnea overnight pulse oximeter monitors usually attach to the wrist and finger.
Where Should Your Pulse Ox Be?
A healthy person’s pulse oximeter reading should be between 95% and 100%.
A reading of 90% to 94% indicates a dangerous situation.
A reading under 90% can be fatal.
Are Pulse Oximeters FDA Approved
The FDA does not “approve” pulse oximeters, but it does “clear” them for marketing.
A manufacturer must get “FDA Clearance” to market its pulse oximeter as a medical device.
FDA and Non-FDA Marketing Literature
Without that clearance, the manufacturer must disavow medical use of its product.
Marketing literature for a pulse oximeter that is not cleared for medical use will state something like: “This product is a non-medical-use product intended for sports and aviation use only.”
Marketing literature of an FDA-cleared oximeter will say something like “This is a medical use, FDA-Cleared pulse oximeter.”
The reality is that you can find consumer level pulse oximeters for sale that are labeled for sports or aviation use only that are just as good as those labeled for medical use.
Some manufacturers sell pulse oximeters that meet FDA guidelines. The devices do not yet have clearance, because getting clearance is a long and expensive process.
Are Pulse Oximeters Hospital Grade?
Most pulse oximeters available to consumers are not hospital grade.
Hospital machines costs thousands of dollars. Home meters cost between $40 and $200.
A home oximeter is not a diagnostic device. It is a monitor and a safety net that informs your decision to seek medical help.
I would not use a home heart monitor to diagnose arrhythmia. I would not use a pulse oximeter to diagnose hypoxemia.
If my pulse oximeter reads is below 95%, I will ask my doctor what to do next.
Pulse Oximeters Prices
Home-use pulse oximeters range from $40 to $120.
The price is not dependent on the FDA-Clearance status.
You can buy an FDA-Cleared meter for $40.
You can also buy a meter that runs for hours to test sleep levels that is not FDA-Cleared and costs $200.
Is a Home Pulse Oximeter a Diagnostic Device?
To be fair, nothing sold over the counter to consumers is a diagnostic device. Just like monitoring for Atrial Fibrillation at home, monitoring oxygen is only a safety net method.
Whether you do or do not have a diagnosable condition is up to your doctor. He or she will use medical equipment designed to diagnose disease.
You buy a pulse oximeter at home as a safety net to catch dangerously low oxygen. Your practitioner will not rely on your home device. He or she will use professional equipment to check your numbers.
Physicians do not rely on non-medical use devices.
The purpose of taking the oxygen levels at home is to prompt you to get more information from your doctor.
What are the Requirements for Pulse Oximeter FDA Clearance?
Some pulse oximeters meet FDA guidelines, but are not yet FDA-Cleared.
With clearance, the oximeter is a medical device available without prescription.
Without clearance, it is a fitness device, not a medical device.
In March of 2013, the FDA issued specific guidelines for obtaining pulse oximeter clearance.
The guidance applies to non-invasive devices designed to measure “arterial blood oxygen saturation and pulse rate.”
The document recommends accuracy testing to achieve device clearance. If the manufacturer can show that their device is substantially similar to another that is already been tested, the manufacturer can use that other device’s testing results as its own.
Manufacturers must submit tests that include subject skin color, because the devices use light scattering patterns to gather their data.
Cleared devices meet electrical and mechanical safety standards. They do not emit electromagnetic fields that can interfere with electronics.
Manufacturers must test their devices to see that they do not cause irritation or toxic reactions.
Which Pulse Oximeters are FDA Cleared?
iHealth and Nonin were two of the first companies to get FDA clearance on their pulse oximeter devices. They marketed earlier versions of their devices as fitness devices aimed at climbers, runners, and aviators. Manufacturers market medical oximeters to people with lung and heart disease.
Nonin oximeter technology is FDA Cleared. Bosch, GE, and Qualcomm use Nonin oximeter technology in their products.
View our favorite FDA-cleared pulse oximeter here (opens in new window): Recommended Pulse Oximeters for COVID-19 & Apnea Monitoring
Are Pulse Oximeters Reliable?
Pulse oximeters from reputable manufacturers offering two-year warranties are reliable. I have read dozens of pulse oximeter reviews and have not seen any complaining of poor customer service or return problems. I have seen vendors offer free replacements should their customers experience any problems with their pulse oximeters.
Are Pulse Oximeters Accurate?
Yes, pulse oximeters are accurate. One study looked at home-use oximeter accuracy compared to medical-use oximeter accuracy. It found that home-use devices were accurate down to 90% blood oxygen readings. Since a reading below 95% is a red flag, I am not worried about home-use oximeters that are inaccurate under 90%. I will already have taken action and will be on a hospital oximeter if my oxygen gets anywhere below 95%. (source)
The ultimate oxygen saturation accuracy test is the arterial blood gas measurement. Home pulse oximeters are slightly less accurate than the blood gas method, but they are also painless and much less expensive.
An oximeter measures how much oxygen the blood is carrying. An arterial blood gas (ABG) directly measures both the amount of oxygen carried by your blood and the actual amount of gases (oxygen and carbon dioxide) that are in your blood. To get an ABG, blood is taken directly out of your artery (usually from the wrist) and can be painful. Oximetry is painless but is not as accurate as an ABG. In addition, a pulse oximeter does not measure your carbon dioxide level.
As long as a home pulse oximeter is used correctly, it is a functional device that can accurately warn the user of a problem.
No device is accurate when improperly used. The patient should not move, should not wear nail polish, and should not test a tattoo site.
Why Would My Pulse Oximeter Quit Working?
Outside of the batteries needing replacement or recharging, an oximeter can fail if the user gives the device bad inputs.
A pulse oximeter uses light to measure colors changes in the blood. Anything blocking the light reading will cause a bad reading.
These problems can prevent a pulse oximeter from working:
- the patient moves
- the light in the room is too bright
- the device is not calibrated to skin pigmentation
- the patient’s nail polish interferes
In a hospital setting, the pulse oximeter might not get a reading if the radiology injected dye into the blood.
Where are Pulse Oximeters Made?
China. Pulse oximeters are made in China. Almost all pulse oximeter manufacturers are based in the United States, but the actual assembly is in China.
- Gurin Products which makes Santamedical pulse oximeters is based in California
- Nonin is based in Minnesota
- FaceLake is based in Illinois
- Zacurate is based in Texas
- Innovo is based in Texas
- contecmed.com Contec is based in China (Jul 1 2020 website is down so I removed link)
- iHealth is based in
- CMI Health is based in Georgia and Ontario
- ADC Medical is based in New York
- Generation Guard is based in
- Quest is based In Wisconsin
- Eastshore is based in Illinois