What Is Pulse Oximetry? Pulse oximetry (often called pulse ox) is a painless test to measure how much oxygen is in the blood. Why Is Pulse Oximetry Done? Doctors may order pulse oximetry to see if there is enough oxygen in the blood. Oxygen levels may be low with lung infections, asthma, heart problems, allergic reactions, after anesthesia, and with other medical conditions. How Should We Prepare for Pulse Oximetry? If your child has nail polish on, the polish may need to be removed to allow the pulse ox to accurately measure the oxygen level. What Happens During Pulse Oximetry? During pulse oximetry, a small clip or bandage is put on a child's finger, toe, foot, or earlobe. This is called a sensor, and uses light to measure how much oxygen is in the blood. Sometimes pulse ox is done once to get a single oxygen reading, and sometimes the sensor is left on for continuous monitoring of oxygen levels. If the sensor isn't put on well, it can affect the reading and make the oxygen level look lower than it actually is. Can I Stay With My Child During Pulse Oximetry? Parents can stay while their child wears the pulse ox sensor. How Long Does Pulse Oximetry Take? It usually takes a few seconds for the sensor to get the reading it needs. If your child is calm and staying still, it can help the pulse ox be more accurate. When Are the Results Ready? Pulse ox results are available immediately. Are There Any Risks From Pulse Oximetry? Pulse oximetry is a safe test. Occasionally, the sensor can cause skin irritation. If you have questions about the pulse ox, speak with the doctor or another health professional on your child's care team. Back to Articles Related Articles When Your Baby’s in the NICU Learn what a NICU visit will be like for your little one, what you can do to help, and how to find support for yourself. Read More When Your Child's in the Pediatric Intensive Care Unit It can be stressful whenever kids are in the hospital — and even more so when they're admitted to the pediatric intensive care unit (PICU). A basic understanding of the PICU can help you feel better prepared to help your child recover. Read More Heart and Circulatory System The heart and circulatory system are our body's lifeline, delivering blood to the body's tissues. Brush up on your ticker with this body basics article. Read More Lungs and Respiratory System By the time we're 70 years old, we will have taken at least 600 million breaths. All of this breathing couldn't happen without the respiratory system. Read More Double Outlet Right Ventricle (DORV) Double outlet right ventricle (DORV) is a heart defect where the aorta connects to the heart in the wrong place. Read More Hypoplastic Left Heart Syndrome (HLHS) Hypoplastic left heart syndrome (HLHS) is a birth defect of a baby’s heart. The left side of the heart doesn’t grow as it should, making it smaller and weaker than normal. Read More Transient Tachypnea of the Newborn (TTN) For some newborns, the first few breaths of life may be faster and more labored than normal because of a lung condition called transient tachypnea of the newborn (TTN). Read More Truncus Arteriosus Truncus arteriosus is a heart defect that happens when a child is born with one large artery instead of two separate arteries. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.