Pulse oximetry tests are an estimation of blood oxygen levels, but they’re typically precise. This is especially true when using high quality equipment found in most medical offices or hospital settings. With this equipment, medical professionals can carry out the tests accurately.
The Food and Drug Administration (FDA)Trusted Source requires that prescription oximeters must provide results within an accuracy range of 4 to 6 percent.
The American Thoracic SocietyTrusted Source says that typically, more than 89 percent of your blood should be carrying oxygen. This is the oxygen saturation level needed to keep your cells healthy.
Having an oxygen saturation temporarily below this level may not cause damage. But repeated or consistent instances of lowered oxygen saturation levels may be damaging.
An oxygen saturation level of 95 percent is considered typical for most healthy people. A level of 92 percent or lower can indicate potential hypoxemia, which is a seriously low level of oxygen in the blood.
Various factors can affect readings, including a person’s skin tone.
A 2020 report compared the accuracy of pulse oximetry tests and blood gas measurements in detecting hypoxemia in Black and white patients.
Researchers found that among Black patients, there were three times as many cases of pulse oximetry tests failing to detect occult hypoxemia when blood gas measurements did so.
Tests like these were developed without considering a diversity of skin tones. The authors concluded that more research is needed to understand and correct this racial bias.