: Oxygen Saturation in Whole Blood

: What This Test Measures

: Oxygen saturation (SaO2) is the proportion of hemoglobin binding sites in your blood that are occupied by oxygen. It is typically measured on a whole blood sample, often arterial blood, and gives a snapshot of how effectively oxygen is moving from your lungs into your circulation.

: Why Your Provider Ordered It

: Healthcare providers order oxygen saturation testing to check lung and breathing function, to monitor oxygen delivery during illness or treatment, and to help interpret conditions that affect oxygen levels in the blood. It is often part of a broader blood gas or respiratory evaluation.

: How the Sample Is Collected

: The test is usually performed on a whole blood specimen. Depending on your situation, blood may be drawn from an artery (commonly the wrist) or another site as determined by your care team. Arterial samples can feel briefly uncomfortable but are generally quick.

: What the Results Mean

: Results are reported as a percentage of hemoglobin saturated with oxygen. Your provider interprets the number together with your symptoms, other blood gas values, and your overall health. Mildly low values can occur with many conditions, while markedly low values may indicate a need for prompt medical attention.