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Pulse Oximetry (Oxygen Saturation Monitoring) via Finger Probe

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

This test measures how much oxygen is bound to your red blood cells while you're resting or during activity. It’s a quick, painless way to check your blood oxygen levels using a small sensor placed on your finger.

Quick summary

["A simple, non-invasive way to monitor oxygen levels in real time."]

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

Key facts at a glance

LOINC
59414-3
Short code
SaO2 pre BD % BldA PulseOx
Synonyms
SaO2 pre BD % BldA PulseOx
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
pulse-oximetry
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

How It Works

A small sensor (probe) is placed on your fingertip. It sends a gentle light through your skin to measure the oxygen levels in your blood. The device then displays a percentage (saturation level) that reflects how well your blood is carrying oxygen.

What to Expect

You’ll likely feel a slight pressure or warmth from the probe, but it won’t hurt. The test takes about 10–30 seconds. If you have very dark skin, the probe may need to be placed on a different part of your body, like your earlobe.

Why It’s Done

Doctors use pulse oximetry to check for breathing problems, monitor oxygen levels during surgery or anesthesia, assess symptoms like shortness of breath, or evaluate conditions like sleep apnea or heart disease.

Normal vs. Abnormal Results

Healthy adults typically have oxygen saturation levels between **95% and 100%**. Levels below 90% may indicate a problem that needs medical attention, such as low blood oxygen (hypoxemia).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

O₂ Saturation Check

Frequently asked questions

What does a low oxygen saturation mean?
A low oxygen saturation (below 90%) can signal underlying health issues like chronic lung disease, heart problems, or even severe infections. It may also occur during sleep disorders like sleep apnea or if you’re exposed to low oxygen environments, such as high altitudes.
How often should I get this checked?
Pulse oximetry is usually done as a one-time check or during specific medical evaluations. If you have a chronic condition (like COPD or heart failure), your doctor may recommend regular monitoring. Always follow your healthcare provider’s advice.
Can I do this test at home?
Yes! Many people use at-home pulse oximeters to monitor their oxygen levels, especially if they have conditions like sleep apnea or asthma. However, these devices aren’t as precise as lab or hospital-grade ones, so consult your doctor if you notice concerning trends.
  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