SpO2 stands for which measurement?

• A. SaO2
• B. SpO2
• C. Pulse Ox
• D. Oxygen Saturation

Answer: (B)

SpO2 is the saturation of peripheral oxygen, the percentage of hemoglobin carrying oxygen as estimated by a pulse oximeter. It’s a noninvasive measure that uses light to infer how much arterial hemoglobin is oxygenated, and it’s usually reported as a percent, typically 95–100% in healthy individuals. This distinguishes it from arterial oxygen saturation measured directly from a blood sample (SaO2), which requires blood gas analysis or co-oximetry. It’s also different from the device label “pulse ox,” which refers to the instrument or method rather than the actual percentage. “Oxygen saturation” is a general term for the concept, but SpO2 is the standard abbreviation for the pulse-oximetry–derived measurement.