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Oxygen Saturation (SpO₂) via Pulse Oximetry Device

Published: August 9, 2026Updated: August 16, 2026

This test measures how much oxygen is bound to hemoglobin in your blood, typically using a finger probe on your skin. It’s a quick, non-invasive way to assess oxygen levels in your bloodstream.

Quick summary

["A pulse oximeter helps monitor oxygen levels safely and conveniently during routine check-ups or at home."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
41926-7
Short code
SaO2% Device Vendor name
Synonyms
SaO2% Device Vendor name
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

How the Test Works

A small sensor attached to your finger or ear measures light absorption to estimate the percentage of oxygen-saturated hemoglobin in your blood. This is a continuous, real-time measurement rather than a drawn blood sample.

What to Expect Before the Test

No special preparation is needed. Simply place the sensor on your finger or ear, and the device will display your oxygen saturation percentage. It’s quick, painless, and can be done while you’re sitting or lying down.

When This Test Might Be Used

Pulse oximetry is commonly used to monitor oxygen levels during sleep studies, before anesthesia, or in patients with suspected low oxygen (hypoxia). It’s also a tool for home monitoring in chronic conditions like heart or lung disease.

Limitations and Considerations

While pulse oximetry is generally accurate, it may not detect all types of anemia or carbon monoxide poisoning. Extremely low temperatures, nail polish, or poor circulation can affect readings. Always consult your healthcare provider if you have concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Pulse Oximetry Oxygen Saturation

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend pulse oximetry to check for low oxygen levels before surgery, during sleep studies, or if you have symptoms like shortness of breath, fatigue, or irregular heartbeat. It helps identify potential breathing issues or heart problems early.
What does a low oxygen saturation mean?
A reading below 95% may indicate low oxygen levels, which can cause fatigue, dizziness, or difficulty breathing. Severe drops (below 90%) may require immediate medical attention, especially if you have lung or heart conditions.
Can I use this test at home?
Yes, many people use pulse oximeters at home to monitor chronic conditions like COPD or sleep apnea. However, always follow your doctor’s guidance on when to use it and report any concerning results immediately.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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