Micah Edwin, MD (Owner/CEO Medwin Clinicians) on Instagram: "Medwin Clinicians Did You Know!!! Medicine: Beyond the Basics. The Science Behind The Pulse Oximeter Your fingertip holds a secret that could save your life, and this tiny device reads it in seconds. A pulse oximeter uses two beams of light, red and infrared, that shine through your finger to measure oxygen levels in your blood. Here’s the fascinating part: oxygen-rich blood absorbs infrared light differently than oxygen-poor blood. Th