How is oxygen saturation typically measured?

Oxygen saturation is typically measured using a pulse oximeter, which is a non-invasive device that estimates the percentage of hemoglobin in the blood that is saturated with oxygen. The pulse oximeter works by shining light through the skin, usually on a fingertip or earlobe, and measuring the amount of light absorbed by oxygenated and deoxygenated hemoglobin.

This method is widely used because it provides immediate results and can be performed quickly and easily in various settings, including clinics, emergency departments, and even at home. It allows healthcare providers to monitor a patient’s oxygen levels continuously and to make urgent decisions regarding their care based on their oxygenation status.

In contrast, measuring oxygen saturation using a blood sample is more invasive, involves blood draws, and is typically reserved for situations where precise measurements of arterial blood gases (ABG) are necessary. A stethoscope is used for auscultation of internal sounds and does not provide any information about oxygen saturation. Lung function tests assess respiratory mechanics and capacity rather than directly measuring oxygen saturation levels.