Platform
Company
Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
This test reports the oxygen saturation measured by a pulse oximeter, a light sensor placed on a finger, toe, or ear that estimates how much of your hemoglobin is carrying oxygen. Some laboratories record the result as a fraction rather than a percentage. Despite the name, it is a noninvasive reading obtained at the skin and reflects how well oxygen is being carried in your bloodstream at the time of measurement.
Pulse oximetry is quick and painless, and it is commonly used alongside your symptoms, vital signs, and other tests to give a real‑time picture of your breathing and circulation.
Oxygen saturation helps your care team judge how effectively your lungs are moving oxygen into your blood and whether your heart and circulation are delivering it to tissues. It is used in urgent care, hospital wards, clinics, and at home to monitor conditions that can affect breathing, such as asthma, COPD, pneumonia, heart problems, or during and after procedures. It also guides decisions about whether supplemental oxygen or other treatments are needed.
Because pulse oximetry provides a rapid estimate, it is often the first signal of a change in respiratory status. It also has limitations, so clinicians consider your history, examination, and other tests before making decisions.
Your result is interpreted in the context of how you feel, your medical conditions, and the clinical setting. If a reading does not fit your symptoms, your clinician may repeat the measurement, adjust the sensor site, or confirm with a blood gas or co‑oximetry test. Day‑to‑day variability can occur, so a single value is less informative than trends over time.
If you use a home device, ensure a proper fit, warm hands, and stillness during measurement. Remove nail polish or artificial nails, and allow time for the reading to stabilize. Contact your clinician if your readings are persistently lower than usual for you, if they suddenly change, or if you develop new symptoms such as worsening shortness of breath, chest discomfort, or confusion.
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, shock, or peripheral vascular disease can reduce blood flow and make the signal weak or unreliable, leading to underestimation or erratic readings.
Shivering, tremors, or movement, and clips that are too loose or too tight can introduce artifact. Keeping still and ensuring a snug, comfortable fit improves accuracy.
Dark polish, gels, and artificial nails can block or scatter the light from the sensor. Removing them or using an alternate site like the ear or forehead can help.
In some people with darker skin tones or thicker skin, certain devices may overestimate saturation. Clinicians may confirm results with additional testing when readings seem inconsistent.
Carboxyhemoglobin from carbon monoxide exposure and methemoglobin can bias pulse oximeter readings. Laboratory co‑oximetry may be needed if these are suspected.
High altitude, very bright ambient light, or temperature extremes can affect readings. Shielding the sensor and allowing time to acclimate can reduce variability.
Drugs that constrict blood vessels or affect heart function can change perfusion at the sensor site and alter the reliability of the reading.
Choosing an appropriate site (finger, toe, ear, or forehead) and rotating sites when needed helps avoid pressure effects and improves signal quality.
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