What’s a Pulse Oximeter, and Do I Really Need One at Home? A tiny fingertip device can give you valuable information about your health during a bout of Covid-19 or any respiratory illness. What is a pulse oximeter? A pulse oximeter is a small device that looks sort of like a chip clip or a big clothespin. You place your finger snugly inside (most require nail side up), and within seconds it lights up with numbers indicating your blood oxygen level and heart rate. Most healthy people will get oxygen reading around 95 to 98 percent. Some people with existing health conditions may have a lower normal reading. You should check in with your doctor if the number falls to 92 or lower. The device will also show your heart rate. A normal resting heart rate for adults ranges from about 60 to 100 beats per minute, although athletes with higher cardiovascular fitness will have a lower pulse. How does a pulse oximeter work? When you insert your finger into a pulse oximeter, it beams different wavelengths of light through your finger (you won’t feel a thing). It’s targeting hemoglobin, a protein molecule in your blood that carries oxygen. Hemoglobin absorbs different amounts and wavelengths of light depending on the level of oxygen it’s carrying. Your pulse oximeter will give you a numerical reading — a percentage that indicates the level of oxygen saturation in your blood. If you’ve been to a doctor in the past 20 years, you’ve experienced pulse oximetry. Does it matter what finger I use? Most health technicians will place the device on the index fingers, but a study of 37 volunteers found that the highest reading came from the third finger on the dominant hand. A close second was the dominant thumb. Do long nails or nail polish make a difference? Yes. Dark nail polish can affect the accuracy of the reading. Very long nails would make it difficult to insert your finger properly in the clip. What happens if my oxygen level falls? What is the treatment? If your number dips to 92 or lower, you should check in with your doctor. But don’t panic. The good news is that it’s a lot easier to bolster an oxygen level that is just starting to drop than one that is dangerously low
Is there a risk of monitoring oxygen levels at home? It’s possible that a home monitor could give a faulty reading or be used incorrectly, prompting a patient to seek care unnecessarily. If you or someone in your home shows a very low reading, you may want to test your device on a healthy person to confirm that it is working correctly and discuss it with your doctor.