What is a pulse oximeter and how can it help detect early stages of COVID-19?


RALEIGH, N.C. (WNCN)- With COVID-19 Cases continuing to rise in North Carolina and other states, people need an early warning that they’re infected.

Doctors say a device called a pulse oximeter can do just that.

CBS 17 consumer investigator Steve Sbraccia put several different kinds of the device to the test to see if they’re reliable.

Back in April as the virus was raging, CBS 17 reported that doctors working in New York City hospital emergency rooms discovered that there was a way to detect COVID-19 in its early stages of infection before you showed major symptoms.

Emergency room physician Dr. Richard Levitan said the disease kills by “silent hypoxia.”

“With this disease is people’s brains are working fine. Their oxygen levels have gone down to scary low levels, but it has happened slow enough that their body has accommodated it,” Levitan explained.

He recommended daily testing with a pulse oximeter.

How does an oximeter work? It uses light to detect the oxygen saturation in your blood.

When you put your finger in the device, the light has to pass through your finger and the arteries that contain your blood which has hemoglobins.

Hemoglobin carries oxygen and it also absorbs light, so the more oxygenated your blood—the more light will be absorbed.

That light absorption is then calculated as a percentage on the oximeter screen.

There are hundreds of oximeters out there— ranging in price from $14 to $500 dollars.

We wanted to know if a cheap one was as effective as an expensive one.

We put two of them to the test, using one that retailed between $60 and $75  and another one that cost $14 on sale, but normally retails for $20.

We first tested the expensive one. With-in 10 seconds, Sbraccia got oxygen level reading that bounced between of 98—99 percent.

The reading fluctuated slightly because that device has a sensor which reads continuously.

Next, Sbraccia tried the less expensive one. It showed an oxygen level of 97 percent.

Once it calculated the reading, that’s what stayed on the screen. It didn’t change as the blood pulsed through his finger.

Both devices provided roughly the same result with negligible variation.

Our conclusion: when it comes to oximeters you place on your finger, it doesn’t matter whether you buy an inexpensive basic model—or a high end model with lots of extra bells and whistles, both are acceptable and will get the job done.

Remember, the oxygen levels in your blood vary slightly from hour to hour and day to day.

A reading of 95 per cent or better is considered normal. A reading of 92 per cent or lower is considered abnormal.

If you see your oxygen levels dropping over a couple of days, call your doctor to discuss the issue.

There are also oximeter apps that you can get for your smartphone.

Although the apps claim to work on the same principal of light passing through your finger, you do not want to use them because experts say they just aren’t accurate.

The Center For Evidence Based Medicine says studies show “there is no evidence any smartphone technology is accurate for measuring blood oxygen saturation for clinical use”… and that ” technologies should not be trusted.”

Availability of the devices has improved in the last month or so.

Many brick and mortar retail outlets now have them in stock, and you can order them online from many outlets without having to wait for a back-order to be filled.

Physicians like Dr. Levitan recommend the pulse oximeter be used daily for the next two years, or until we get a handle on the COVID-19 virus.

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