Oxygen Saturation in Whole Blood (SaO₂)
This test measures how well your blood is carrying oxygen, which is essential for your body’s cells to function properly.
["Assesses your blood’s ability to deliver oxygen to tissues, critical for overall health and breathing efficiency."]
Key facts at a glance
- LOINC
- 8849-2
- Short code
- SaO2 % DA
- Synonyms
- SaO2 % DA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Does This Test Measure?
Your blood’s oxygen saturation level, expressed as a percentage. It reflects the proportion of hemoglobin molecules bound to oxygen in your red blood cells. Normal levels typically indicate healthy oxygen transport, while lower levels may signal issues like poor circulation, lung problems, or anemia.
Why Might You Need This Test?
Doctors may order this test to evaluate lung function, detect anemia, assess blood flow problems, or monitor conditions like heart disease, chronic obstructive pulmonary disease (COPD), or sleep apnea. It’s also used during surgeries, in intensive care units, or before procedures requiring oxygen therapy.
How Is the Test Performed?
A small blood sample is taken from a vein, usually in your arm. The sample is analyzed in a lab to measure the oxygen saturation level. This test is quick and painless, often done with a finger-prick probe if using a pulse oximeter for bedside monitoring.
What Are Common Results and Next Steps?
Results are presented as a percentage (e.g., 95%). Low levels (below 90% in some cases) may prompt further testing or treatment for underlying conditions. High levels (above 100% in some cases) are rare but can occur with certain medications or conditions like polycythemia.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low oxygen saturation can indicate serious health issues, such as respiratory failure, heart problems, or blood disorders. It’s a critical marker for conditions affecting oxygen delivery, like severe anemia, lung diseases (e.g., pneumonia, emphysema), or blood clots blocking arteries. High levels may suggest conditions like high-altitude sickness or overproduction of red blood cells.
Short name
Oxygen Saturation
Frequently asked questions
What Does a Low Oxygen Saturation Level Mean?
How Often Should I Get This Test?
Can I Prepare for This Test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy