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Oxygen Saturation in Whole Blood (via Pulse Oximetry)

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

This test measures how much oxygen is bound to hemoglobin in your blood, typically done using a finger probe during routine checkups or monitoring.

Quick summary

["Assesses oxygen delivery efficiency in your bloodstream."]

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

Key facts at a glance

LOINC
8855-9
Short code
SaO2 % SVC
Synonyms
SaO2 % SVC
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 This Test Works

A small sensor placed on your finger (pulse oximeter) measures light absorption to estimate the percentage of oxygen-saturated hemoglobin. This is a non-invasive, painless method often used in clinics or at home.

When You Might Need It

Doctors may order this test to evaluate lung function, check for conditions like anemia, heart disease, or poor circulation, or monitor chronic illnesses such as COPD or heart failure.

What to Expect

You’ll place your finger on the sensor, and the device will send a gentle light through your skin. It takes just seconds, and you can continue normal activities afterward.

Common Conditions Monitored

Oxygen saturation helps identify issues like low oxygen levels (hypoxemia), which can occur with breathing problems, blood disorders, or severe infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

O₂ Saturation

Frequently asked questions

Why does my doctor ask for this test?
Your doctor may recommend it to check if your body is getting enough oxygen, especially if you have symptoms like shortness of breath, fatigue, or a history of lung or heart issues.
What do the results mean?
A normal range is typically between 95% and 100% for healthy individuals at rest. Values below 90% may indicate a need for further medical evaluation, while values above 100% are rare and often due to technical factors or conditions like polycythemia.
Can I do anything to prepare for this test?
No special preparation is needed. Wear comfortable clothing, and avoid removing nail polish if the sensor is placed on your finger.
  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