Pulse oximeters should not be used to diagnose Covid-19, US FDA says

Pulse oximeters, devices which measure oxygen levels in blood, should not be used to diagnose Covid-19 and could give inaccurate readings under certain circumstances, the US Food and Drug Administration warned on Friday.

In January, the World Health Organisation included use of pulse oximeter to identify patients who might need hospitalisation in its clinical advice for treating Covid-19.

But the FDA said the devices cannot be used to diagnose or rule out Covid-19, and generally it recommended not relying on them to assess health.

It recommended paying attention to other indicators of low oxygen, such as blueness of the face or a racing pulse.

The US health agency said the device might be “useful” for estimating blood oxygen levels, but multiple factors can affect the accuracy of a pulse oximeter reading, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use and use of fingernail polish.

The warnings come nearly two months after a study published in New England Journal of Medicine showed that the device was three times more likely to give misleading readings among African-American patients.

During the pandemic, the devices have also become a widely sold item online, used by people to monitor their own oxygen levels at home.

However, over-the-counter oximeters sold in stores or online do not undergo FDA review and are not intended for medical purposes, the agency said.