Platform
Company
Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
This test reports your oxygen saturation as measured by a pulse oximeter, a small sensor placed on a fingertip, toe, or ear. It shines light through your skin and estimates the fraction of hemoglobin in your blood that is carrying oxygen. The result reflects how well oxygen is being transported from your lungs to your bloodstream at the time of the reading.
Because the measurement is noninvasive and quick, it is commonly used in clinics, emergency departments, and at home to monitor breathing problems, recovery from illness, or response to treatment. Results are presented as a fraction, which corresponds to a percentage of hemoglobin bound to oxygen.
Oxygen saturation helps your care team assess whether your lungs and heart are delivering enough oxygen to your body. It is often checked if you have symptoms such as shortness of breath, chest discomfort, or bluish lips or fingers, and it is routinely monitored during procedures, after surgery, and when you receive medications that can affect breathing.
This test supports decisions about oxygen therapy and other treatments in conditions like asthma, chronic obstructive pulmonary disease, pneumonia, heart failure, and respiratory infections. It also helps track trends over time, which can reveal improvement or worsening even before you notice changes in symptoms.
Your result should be interpreted alongside how you feel, your medical history, and other tests. Readings can vary with activity, altitude, temperature, and circulation to the finger or ear. A single unexpected value may reflect sensor placement or motion, so repeating the measurement after warming your hands, removing nail polish, or trying a different finger can be helpful.
If readings repeatedly appear lower or do not match how you feel, your clinician may confirm with a blood test from an artery or use specialized testing to check for hemoglobin variants or exposures that affect accuracy. Seek medical care promptly if you have persistent shortness of breath, chest pain, confusion, or a change in skin color, regardless of the number on the device.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Cold hands, low blood pressure, or tight vasoconstriction reduce blood flow to the sensor site and can cause unreliable or low readings. Warming the hand and relaxing the limb can improve accuracy.
Dark nail polish, artificial nails, skin dyes, and strong ambient light can interfere with light transmission and skew results. Remove polish or use a probe on the ear or an alternate finger if possible.
Shaking, tremors, or a loose or misplaced sensor can confuse the device and generate erratic numbers. Keep still, ensure a snug fit, and wait for a stable pulse waveform before recording a value.
Carbon monoxide exposure from smoking or environmental sources, and certain oxidant stresses or drugs, can alter hemoglobin and lead to falsely high or low readings. Laboratory co-oximetry may be needed.
Intravenous dyes such as methylene blue or indocyanine green, and vasoconstrictors that reduce blood flow, can affect accuracy. Tell your clinician about recent procedures and medications.
Living at high altitude and conditions that affect ventilation or circulation can change expected values and day-to-day variability. Your clinician will interpret results in the context of your baseline.
Infants, people with darker skin tones, arrhythmias, anemia, or peripheral vascular disease may have measurement biases or variability. Alternative sites or confirmatory tests may be recommended.
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