Oxygen Saturation (Arterial Blood Gas)
This test measures how well your blood is carrying oxygen, typically taken from an artery in your arm or wrist. It helps doctors check for problems like low oxygen levels, breathing difficulties, or heart conditions.
["Assesses oxygen efficiency in your blood—critical for breathing and overall health."]
Key facts at a glance
- LOINC
- 85353-1
- Short code
- Vitals+wt+ht+hc+SaO2+BMI Pnl
- Synonyms
- Vitals+wt+ht+hc+SaO2+BMI Pnl
- 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
Why It’s Done
Your healthcare provider may order this test if you have symptoms like shortness of breath, rapid breathing, chest pain, or fatigue. It’s also used before surgeries, during anesthesia, or to monitor chronic conditions like heart or lung diseases.
What to Expect
A small needle is inserted into an artery in your arm or wrist to draw a tiny blood sample. The test is quick but may cause a brief pinch. You’ll likely feel a slight sting, but it’s over in seconds. No special preparation is needed.
How It Works
The blood sample is analyzed to measure the percentage of oxygen bound to hemoglobin (hemoglobin saturation). This is done using specialized equipment that detects oxygen levels in real time.
Normal vs. Abnormal Results
While reference ranges can vary by lab, a typical healthy range is between 95% and 100%. Values below 90% may indicate low oxygen levels, which could signal issues like pneumonia, heart failure, or respiratory problems.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low oxygen saturation (hypoxemia) can cause serious health risks, including organ damage, confusion, or even life-threatening conditions. High saturation (above 100%) is rare but may occur in conditions like carbon monoxide poisoning. Regular monitoring helps manage chronic diseases and guide treatment decisions.
Short name
SpO₂ (Oxygen Saturation)
Frequently asked questions
What causes low oxygen levels?
How is oxygen saturation tested?
Can I eat or drink before 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