Oxygen Saturation During Inspiration (SaO₂) – Partial Pressure of Oxygen in Blood
This test measures how much oxygen is dissolved in your blood when you breathe in, helping assess lung function and oxygen delivery.
["A key indicator of lung health and oxygen levels in your bloodstream during breathing."]
Key facts at a glance
- LOINC
- 76106-4
- Short code
- O2 during insp VFr/PPres Gas DS.IL
- Synonyms
- O2 during insp VFr/PPres Gas DS.IL
- 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 This Test Measures
Your blood contains dissolved oxygen, which is measured here as a partial pressure (SaO₂) when you inhale. This reflects how efficiently your lungs transfer oxygen into your bloodstream. Unlike standard oxygen saturation tests (like pulse oximetry), this test specifically looks at dissolved oxygen levels rather than hemoglobin-bound oxygen.
Why It’s Done
Doctors may order this test if you have symptoms like shortness of breath, chronic lung conditions (such as COPD or asthma), or suspected issues with oxygen exchange. It helps evaluate lung function, identify breathing problems, or monitor conditions affecting oxygen delivery.
How It’s Performed
A small blood sample is taken from your arm or hand, typically via a needle. The sample is analyzed in a lab to measure dissolved oxygen pressure during inspiration. This is often done alongside other blood gas tests (like pH or carbon dioxide levels).
What to Expect Before or After
There are no special preparations needed. You may feel slight discomfort from the needle, but it usually goes away quickly. If you’re taking blood from your hand, keep it warm afterward to reduce swelling.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low SaO₂ values during inspiration can indicate lung diseases, poor ventilation, or conditions that reduce oxygen uptake (e.g., pneumonia, pulmonary edema, or severe asthma). High values may suggest hyperventilation or other metabolic factors. This test helps guide treatment for breathing disorders or oxygen therapy needs.
Frequently asked questions
How does this test differ from a pulse oximeter reading?
What does a low SaO₂ value mean?
Can I fast 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