Final answer:
Oxygen saturation, also known as percent saturation, is typically measured using a pulse oximeter, with normal readings ranging from 95-100 percent. Below-normal readings indicate hypoxemia, and direct arterial blood testing measures oxygen levels as partial pressure of oxygen (pO2).
Step-by-step explanation:
Oxygen saturation (O2 sat) is a non-invasive measurement of arterial blood oxygen saturation, also referred to as percent saturation or "percent sat." To monitor this, healthcare professionals use a pulse oximeter, which is placed on a thin part of the body, like a fingertip, to measure the oxygen bound to hemoglobin in the blood. The device emits two wavelengths of light (red and infrared) that pass through the finger. Differing absorption levels, based on the hemoglobin's oxygen saturation, allow the oximeter to calculate percent saturation.
Normal pulse oximeter readings range from 95-100 percent. Readings below this range may indicate hypoxemia, or low blood oxygen levels. When arterial blood is tested directly (arterial stick), oxygen levels are given in terms of partial pressure of oxygen (pO2), usually measured in millimeters of mercury (mm Hg).