Pulse oximetry is a test that measures the amount of oxygen present in the blood. This diagnostic test uses a medical device known as a pulse oximeter to measure the levels of oxygen in the blood, as well as the pulse rate, without having to take a blood sample. Pulse oximetry is a non-invasive test that causes no pain or discomfort. A pulse oximeter is often used in a hospital setting when a patient is admitted to the emergency room for diagnostic purposes, or during surgery, to monitor pulse rate and oxygen levels. A pulse oximetry test is commonly used to evaluate or diagnose various medical conditions that affect the function of the heart and lungs.
During pulse oximetry testing, the small pulse oximeter device is commonly placed on the fingertip or earlobe to perform the reading. Using special lights and sensors, the machine can measure the oxygen saturation of the blood. Pulse oximetry takes only a few minutes to perform. Normal pulse oximeter readings range from 95 to 100 percent. Readings under 90 percent are considered low and may indicate a problem in the function of the cardiovascular or pulmonary system. After a low pulse oximetry reading, additional testing may be required to determine the exact cause and further diagnose any related conditions.