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Oxygen Saturation in Whole Blood (Arterial)

Published: August 9, 2026Updated: August 17, 2026

This test measures how well oxygen is being carried in your blood from your lungs to the rest of your body. It helps assess your oxygen levels and overall lung function.

Quick summary

["Check your oxygen levels to identify potential lung or heart issues."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
74105-8
Short code
SaO2 % BldMV from pO2
Synonyms
SaO2 % BldMV from pO2
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
80
Ref high
100
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
calculated-from-oxygen-partial-pressure
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

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like shortness of breath, fatigue, or if you have a condition that could affect how well your blood carries oxygen, such as heart disease, lung problems, or anemia.

What to Expect Before the Test

You’ll likely have a small needle inserted into your arm or hand to draw a small amount of blood. The process is quick and usually doesn’t cause discomfort. If you’re anxious, let your provider know so they can help you relax.

How the Test Results Are Used

Results help doctors determine if your oxygen levels are within a healthy range. Low oxygen levels may indicate problems like poor lung function, heart issues, or other health concerns that need further evaluation.

Common Conditions Affecting Oxygen Saturation

Conditions like chronic obstructive pulmonary disease (COPD), asthma, heart failure, or even high altitudes can lower oxygen saturation. Smoking, infections, or blood disorders may also impact these levels.

Reference range

NCBI: PaO2 80-100 mmHgN/A

Specimen: whole-blood

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

O₂ Saturation (Arterial Blood)

Frequently asked questions

What does an abnormal oxygen saturation result mean?
An abnormal result may mean your blood isn’t carrying enough oxygen, which could be due to lung issues, heart problems, or other health conditions. Your doctor will discuss the results with you and may recommend further tests or treatments.
How often should I get this test?
The frequency depends on your health condition. If you have a chronic illness like COPD or heart disease, your doctor may order this test regularly. Otherwise, it’s usually done only when symptoms or other test results suggest you need it.
Can I eat or drink before this test?
You can eat and drink normally before the test unless your doctor advises otherwise. No special preparation is needed for this simple blood draw.
  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 17, 2026. · Read our editorial policy