Vital signs
Oxygen Saturation
LOINC 59408-5 · %
Ranges
Reference range: 95–100 %
What it is
Oxygen saturation (SpO2) is the percentage of your red blood cells carrying oxygen, usually measured with a fingertip sensor.
Why it matters
It is a quick check of how well your lungs and circulation are delivering oxygen. Normal is usually 95–100%.
What high values can mean
A higher value within the normal range is good; readings above the range are not typical of routine measurement.
What low values can mean
A lower value can indicate your body is not getting enough oxygen and may need prompt attention.
How to improve it
Oxygen levels reflect lung and heart function; treating any underlying condition is what improves a low reading.
Food & lifestyle
Not smoking and treating lung or heart conditions support healthy oxygen levels; readings aren't changed by diet.
Preparing for the test
Keep your hand warm and still; cold hands, nail polish or movement can affect a fingertip reading.
When to talk to a doctor
Seek urgent care for a persistently low oxygen level or breathlessness.
Related markers
Sources
- MedlinePlus (NIH)
- Cleveland Clinic
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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