Pulse Oximetry
Reviewed
Also called: Pulse Ox, Oxygen saturation monitor, Finger pulse oximeter
Pulse oximetry is a quick, painless test that uses a small clip-like device (pulse oximeter) on a fingertip to measure the oxygen level in your blood. It is used to check for low blood oxygen (hypoxemia) in various settings, including routine checkups, monitoring of lung conditions, during surgery, and at home. The test carries no known risks, but factors like dark nail polish, artificial nails, darker skin pigmentation, poor circulation, cold skin, and tobacco use can affect accuracy. Results are typically given as a percentage (oxygen saturation). A normal level is 95%–100%, but lower levels may be acceptable for some individuals with chronic lung disease or at high altitudes. Contact your provider if your level is 92% or lower; seek immediate medical attention if it is 88% or lower. The test results may be 2% to 4% higher or lower than your actual blood oxygen level. For more precise measurement, your provider may order an arterial blood gas test.
Specimen: None
Urgent safety information
Seek immediate medical attention if your oxygen saturation level is 88% or lower, or if you experience symptoms of low oxygen (e.g., bluish lips/nails/face, trouble breathing, chest pain, fast heart rate).
Why this test may be ordered
- To check blood oxygen level as part of a routine checkup.
- To monitor lung function in conditions like COPD, lung cancer, heart failure, asthma, or COVID-19.
- To assess the effectiveness of medicines for lung disease.
- To monitor oxygen levels before, during, and after surgery.
- To evaluate for sleep apnea (repeated breathing pauses during sleep).
Preparation and collection
Remove dark nail polish from the finger being tested. Avoid artificial nails on that finger. Inform your provider about factors that could affect accuracy (e.g., poor circulation, cold skin, tobacco use).
None
There is no known risk to having pulse oximetry. The device uses light and is painless.
Understanding results
Pulse oximetry measures the percentage of oxygen-saturated hemoglobin in your blood (oxygen saturation). Results are typically reported as a percentage. Interpretation depends on your overall health, altitude, and any underlying lung conditions. The following patterns are based on the MedlinePlus source.
- 95% to 100%: Your blood oxygen level is in the normal range for a healthy person. Limitation: Results may be 2% to 4% higher or lower than actual oxygen level. Normal for healthy individuals is 95%–100%. Lower levels may be acceptable for people with chronic lung disease or at higher altitudes; consult your provider. Next step: No immediate action needed. Continue routine monitoring as recommended by your provider.
- 92% or lower (but above 88%): Your blood oxygen level is lower than the normal range for a healthy person. This may indicate hypoxemia or be expected for your condition. Limitation: Results may be 2% to 4% higher or lower than actual oxygen level. This range may still be acceptable for some individuals with chronic lung disease, but you should contact your provider for guidance. Next step: Contact your healthcare provider to discuss your oxygen level and any symptoms.
- 88% or lower: Your blood oxygen level is dangerously low (severe hypoxemia) and requires urgent care. Limitation: Results may be 2% to 4% higher or lower than actual oxygen level. This is a critical level requiring immediate medical attention. Next step: Seek immediate medical attention. If you are using an at-home oximeter and your level is 88% or lower, call 911 or go to the emergency room.
- Dark nail polish, artificial nails, darker skin pigmentation, poor circulation, cold skin, and tobacco use may cause inaccurate results.
- Pulse oximetry results may be 2% to 4% higher or lower than the actual blood oxygen level.
- The test reflects oxygen saturation but does not measure other blood gas parameters; a more accurate measurement may require an arterial blood gas test.
What to do next
Discuss results with your healthcare provider. For at-home monitoring, follow your provider's guidance on when to contact them or seek emergency care.
- What is my oxygen saturation level?
- Do I need to monitor my oxygen levels at home?
- What should I do if my oxygen level falls below 92%?
- How does my lung condition affect my target oxygen level?