Serum Oxygen Saturation (Partial Pressure)

What This Test Measures

The test evaluates the partial pressure of oxygen (measured in millimeters of mercury, mmHg) bound to hemoglobin in your blood. This reflects how well oxygen is being transported from the lungs to tissues. It’s particularly useful in diagnosing conditions affecting oxygen delivery, such as respiratory disorders or anemia.

Why It’s Done

Your healthcare provider may order this test if you have symptoms like shortness of breath, fatigue, or signs of poor oxygenation (e.g., blue lips or skin). It’s also used in monitoring patients with chronic lung diseases, heart conditions, or those undergoing treatments that could affect oxygen levels.

Common Uses

Common reasons include evaluating lung function, assessing oxygenation in critical care settings, or monitoring conditions like chronic obstructive pulmonary disease (COPD), sleep apnea, or anemia.

How the Test Works

This is typically measured directly from an arterial blood sample (whole blood) using specialized equipment that analyzes oxygen binding to hemoglobin. Unlike a standard blood draw, an arterial sample is taken from a blood vessel in your arm or wrist.