Oxygen Saturation in Whole Blood (Arbitrary Units Concentration)
This test measures how well oxygen is bound to hemoglobin in your blood, expressed as a percentage of oxygen saturation. It’s commonly used to assess lung function and blood oxygen levels.
["Helps diagnose and monitor conditions affecting oxygen delivery in your body."]
Key facts at a glance
- LOINC
- 71842-9
- Short code
- SaO2 DF BldC from pO2
- Synonyms
- SaO2 DF BldC from pO2
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 80
- Ref high
- 100
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- calculated-from-oxygen-partial-pressure
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
Oxygen saturation (SpO₂) reflects the proportion of hemoglobin molecules carrying oxygen in your red blood cells. This value is typically measured using a pulse oximeter, but blood tests can also provide this data when whole blood is analyzed. It’s not the same as measuring actual oxygen levels in your bloodstream but gives insight into how efficiently oxygen is transported.
Why It Matters in Your Health
Abnormal oxygen saturation levels can indicate issues like poor lung function, heart problems, anemia, or even exposure to low-oxygen environments. High levels may suggest conditions like polycythemia (too many red blood cells), while low levels can signal respiratory or circulatory concerns.
Common Conditions Affecting Results
This test is often ordered when you have symptoms like shortness of breath, fatigue, or cyanosis (bluish skin). It may also be used before surgeries, during anesthesia, or in patients with chronic lung diseases like COPD or asthma.
What to Expect Before the Test
No special preparation is needed. A healthcare provider will take a small blood sample from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. If you’re anxious, let your provider know so they can prepare you.
Reference range
NCBI: PaO2 80-100 mmHgN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Oxygen saturation is a critical marker for assessing respiratory and cardiovascular health. Low levels (typically below 90%) can prompt further investigation into conditions like pneumonia, heart failure, or sleep apnea. High levels may require evaluation for conditions like dehydration or overproduction of red blood cells.
Short name
O₂ Saturation (Whole Blood)
Frequently asked questions
How is this test different from a pulse oximeter reading?
Can diet or exercise affect my oxygen saturation levels?
What if my oxygen saturation is outside of normal ranges?
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 17, 2026. · Read our editorial policy