It has long been a confusion among users of pulse oximeter devices about the fact that nail polish affects the actual readings of the device. The way to really answer this is actually to look at how a pulse oximeter actually functions. Essentially the device works by utilizing an infrared light that passes through the skin of the person's finger who is using the device.
That light goes through the skin and actually has a different response depending on the hemoglobin that is present in the tissue. Essentially hemoglobin is what makes up the blood and it absorbs light at a different frequency than other types of systems in the blood. As such the light that passes through the finger bounces off that system and the other part of the light passes through the finger. This in turn will give the reading of the pulse rate and the blood oxygen saturation.
When nail polish is used and then a pulse oximeter device is used what happens is that the nail polish in essence blocks the infrared light from passing through the finger. So what this means is that the computer that is in the oximeter will not be able to compute properly the percentage of light that passed through and the percentage of light that actually came back to the device.
It is often times recommended that individuals not wear nail polish when they are going to use the product. This is good practice because you will be able to get the most amount of accuracy from the product. So if you are wearing some go ahead and remove it temporarily and begin to use your product. You will notice that the readings will start to look much more normal and within line than they looked previously when you had it on your finger.
