Oxygen Saturation in Whole Blood (Pulse Oximetry)
This test measures how much oxygen is bound to hemoglobin in your blood, typically done using a finger probe during a routine check. It reflects your body’s ability to deliver oxygen to tissues.
["A pulse oximeter provides a quick, non-invasive snapshot of your oxygen levels, often used to monitor breathing efficiency or detect potential issues like low oxygen."]
Key facts at a glance
- LOINC
- 59415-0
- Short code
- SaO2 pre PT % BldA PulseOx
- Synonyms
- SaO2 pre PT % BldA PulseOx
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- pulse-oximetry
- CPT
- 85610
- SNOMED
- 396252006
- 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
Pulse oximetry measures the percentage of hemoglobin in your red blood cells that is saturated with oxygen (SpO₂). This is a continuous, real-time measurement taken via a sensor placed on a finger, toe, or ear lobe. The device also detects your heart rate. Unlike blood tests, this method does not require drawing blood and is generally safe for all ages.
How It’s Performed
You’ll place a small sensor on your fingertip or another part of your body with good circulation. The sensor emits light that passes through your skin and blood vessels. The device analyzes the reflected light to calculate oxygen saturation and heart rate. The process takes just a few minutes and is painless.
When It’s Used
Pulse oximetry is commonly used in hospitals, clinics, and even at home to monitor oxygen levels in patients with breathing issues, heart conditions, or during anesthesia. It’s also a quick screening tool for conditions like sleep apnea or low blood oxygen (hypoxia).
Limitations and Considerations
While pulse oximetry is generally accurate, it may not always reflect true blood oxygen levels in certain situations. For example, it can be less reliable in people with dark skin tones, cold extremities, or certain medical conditions like severe anemia or carbon monoxide poisoning. Always follow up with a healthcare provider if you have concerns.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
O₂ Saturation
Frequently asked questions
Why might my doctor order this test?
What do my results mean?
Can I do this test at home?
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