Oxygen saturation in whole blood measured by pulse oximetry
This test measures how much oxygen is bound to hemoglobin in your blood, typically taken from a fingerstick or ear lobe. It’s a quick, non-invasive way to assess oxygen levels in your bloodstream.
["SpO₂ helps monitor oxygen availability during routine checkups or in response to health conditions like breathing difficulties."]
Key facts at a glance
- LOINC
- 97552-4
- Short code
- OxyHgb MFr BldCV
- Synonyms
- OxyHgb MFr BldCV
- Category
- hematology
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- 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
How SpO₂ Works
A small sensor attached to your finger or ear measures light absorption through your blood vessels. Oxygenated hemoglobin absorbs different light wavelengths than deoxygenated hemoglobin, allowing the device to calculate your oxygen saturation percentage.
When You Might Need This Test
Doctors may order SpO₂ testing during routine physical exams, before surgeries, or if you have symptoms like shortness of breath, fatigue, or chronic health conditions like heart or lung disease.
Normal vs. Abnormal Results
While reference ranges vary slightly by device and patient factors, healthy adults typically have SpO₂ readings between 95% and 100%. Values below 90% may signal potential issues that need further medical evaluation.
Common Reasons for Testing
SpO₂ is often used to screen for conditions like anemia, sleep apnea, or to monitor oxygen levels during recovery from illness or surgery. It’s also a critical tool in emergency settings for patients with respiratory distress.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/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.
◆Associated findings1
Short name
SpO₂ (Pulse Oximetry Oxygen Saturation)
Frequently asked questions
What does a low SpO₂ reading mean?
How can I improve my SpO₂ levels if they’re low?
Is SpO₂ testing painful?
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