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Oxygen Saturation in Whole Blood (Pulse Oximetry) Over 24 Hours

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

This test measures the highest level of oxygen bound to hemoglobin in your blood over a 24-hour period using a pulse oximeter—a small sensor placed on your finger.

Quick summary

["Helps assess how well your body delivers oxygen during daily activities."]

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

Key facts at a glance

LOINC
59405-1
Short code
SaO2 8h Max % BldA PulseOx
Synonyms
SaO2 8h Max % 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

What This Test Measures

A pulse oximeter continuously monitors oxygen saturation (SpO₂) in your bloodstream, reflecting how effectively oxygen is carried by red blood cells. This test captures the peak values recorded during the 24-hour period, which can indicate variations in oxygen levels due to activity, sleep, or health conditions.

Why It’s Done

Your healthcare provider may order this test to evaluate chronic oxygen levels, especially in patients with suspected sleep-related breathing disorders (like sleep apnea), chronic lung conditions, or other cardiovascular issues. It helps identify patterns that may not be apparent from a single measurement.

How It Works

The test uses a non-invasive sensor attached to your finger to measure oxygen saturation in whole blood. Data is collected continuously and recorded for analysis, with the maximum value noted over the 24-hour period.

Preparation

No special preparation is needed. Wear loose clothing to the test site, and avoid removing the sensor unless instructed otherwise. You may need to stay still for short periods to ensure accurate readings.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Max Oxygen Saturation by Pulse Oximetry

Frequently asked questions

How does oxygen saturation vary during different times of the day?
Oxygen saturation can fluctuate naturally throughout the day due to factors like breathing patterns, physical activity, or sleep cycles. Abnormal patterns—such as consistently low values during sleep or at rest—may signal underlying conditions like sleep apnea, lung disease, or anemia.
What does a high maximum oxygen saturation mean?
A high maximum saturation (above typical reference ranges) might suggest efficient oxygen delivery, but it can also indicate conditions like polycythemia (increased red blood cells) or other metabolic factors. Always discuss results with your provider.
Can this test detect sleep apnea?
While pulse oximetry can identify severe drops in oxygen saturation, it’s not a definitive sleep study. Sleep apnea is typically diagnosed through overnight monitoring (polysomnography) to assess breathing patterns and oxygen levels during sleep.
  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