How is a pulse oximetry screen performed?

Pulse oximetry screening is done when a baby is at least 24 hours of age, or as late as possible if the baby is to be discharged from the hospital before he or she is 24 hours of age.

The test is done using a machine called a pulse oximeter, with sensors placed on the baby's skin. The test is painless and takes only a few minutes.

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The pulse oximeter has a lighted probe that is temporarily attached to the baby’s finger, ear lobe or foot. The light is not hot and will not cause a burn if left attached to the body. Once the baby’s finger is attached to the probe (usually by a sticker), the red light of the probe reads the amount of oxygen carried by the blood. The oxygen level is tested in both arms and both feet. With some kinds of congenital heart disease, the numbers can be different in the arms compared to the legs. It also helps to validate the test to do it in all of the extremities. The time required to complete this test is approximately 1 to 5 minutes.