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Oxygen Saturation (SaO₂) via Pulse Oximetry Device

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

This test measures the percentage of oxygen bound to hemoglobin in your blood, detected by a small sensor on your finger or toe. It’s commonly used to monitor oxygen levels during routine check-ups or in response to health concerns like shortness of breath.

Quick summary

This test helps assess how well your body is delivering oxygen to your tissues, often checked with a handheld device at your doctor’s office.

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

Key facts at a glance

LOINC
73804-7
Short code
SaO2% Device SaO2% sensor name
Synonyms
SaO2% Device SaO2% sensor 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 (probe) is placed on your finger, toe, or ear lobe. The sensor emits light that passes through your blood vessels, measuring how much oxygen is bound to hemoglobin. This process is quick and painless, typically taking just a few seconds.

What to Expect Before the Test

No special preparation is needed. You may remove any nail polish from the finger or toe where the sensor will be placed, as it can interfere with the accuracy of the reading. Wear loose clothing to avoid restricting blood flow to the sensor area.

Common Uses

Doctors use this test to evaluate lung function, check for conditions like sleep apnea, monitor chronic respiratory diseases, or assess oxygen levels during surgeries or other medical procedures.

Potential Limitations

While pulse oximetry is generally accurate, it may not detect low oxygen levels as precisely as blood gas tests, especially in people with dark skin tones or certain medical conditions like severe anemia or carbon monoxide poisoning.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

SaO₂ (Pulse Oximetry)

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend this test if you have symptoms like dizziness, rapid breathing, fatigue, or if they suspect a condition affecting your lungs or heart. It’s also used during routine check-ups or before certain medical procedures to ensure your oxygen levels are stable.
What do abnormal results mean?
Low oxygen levels (hypoxemia) may indicate problems with your lungs, heart, or circulation. High oxygen levels (hyperoxemia) can sometimes occur with certain breathing treatments or medical conditions. Always discuss your results with your healthcare provider, as they’ll interpret the results in the context of your overall health.
Can I take anything before this test?
No, you can eat, drink, or take medications as usual. Avoid removing the sensor probe yourself, as it’s designed to be safe and accurate for your healthcare provider’s use.
  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