What is pulse oximetry?

A pulse oximetry screen is a noninvasive (and painless) test performed on all newborn babies to determine the level of oxygen in their blood. This test uses rays of light of different wavelengths to measure the percent of hemoglobin (the part of blood that carries oxygen) that is filled with oxygen. Normally, a newborn baby should have an oxygen saturation level that is greater than 95 percent.

Screening using pulse oximetry can detect congenital heart disease that may otherwise go undetected for a while. There are some congenital heart defects that cause a newborn baby to have lower oxygen saturation in the blood after birth. It often can be difficult to determine if a baby has cyanosis (bluish discoloration of the skin due to poor oxygen content of the blood) just by looking at him or her after birth.

Newborn screening using pulse oximetry is a tool that can identify some of the babies born with a critical congenital heart defect or disease (critical CHD), so they can receive prompt care and treatment.

About 1 in 4 babies born with a heart defect has a critical CHD and needs surgery or other procedures in the first year of life. Some babies born with a critical CHD appear healthy at first, and they may be sent home before their heart defect is detected. These babies are at risk of having serious complications within the first few days or weeks of life and often require emergency care. Timely care may prevent disability or death early in life.

A pulse oximetry screen estimates the amount of oxygen in a baby’s blood. Low levels of oxygen in the blood can be a sign of a critical CHD. 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.

Pulse oximetry screening does not replace a complete history and physical examination, which sometimes can detect a critical CHD before oxygen levels in the blood become low. Pulse oximetry screening, therefore, should be used along with the physical examination.

In 2011, screening for critical CHD was added to the Recommended Uniform Screening Panel for newborn screening. Currently, many states have passed a law or regulation that will require hospitals to screen newborns for critical CHD. Many hospitals in the remaining states choose to screen newborns, even though their state does not require it.

To check for problems with your lungs and heart, your healthcare provider may order a pulse oximetry test. Pulse oximetry measures how well oxygen is being delivered throughout your body. In this test, a small clip is attached to one of your fingers. The clip shines an infrared light through your skin and registers the amount of oxygen in your tissues. A pulse oximeter (also known as an oxygen saturation monitor) displays this amount as a percentage.

If your oxygen saturation level is consistently below 90%, you may need extra oxygen. This will help prevent further damage to your heart and other tissues.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.