Pulse oximeters, which have increased in use during the pandemic, may yield inaccurate results, the US Food and Drug Administration warned Friday.

Earlier in week, the US Centers for Disease Control and Prevention also updated its coronavirus clinical guidance to warn doctors and nurses that data from several studies suggest skin pigmentation can affect the accuracy of the devices.

"While pulse oximeters may be useful for estimating blood oxygen levels, these devices have limitations that can result in inaccurate readings," Dr.

For each patient, they compared the oxygen levels recorded by a pulse oximeter to those measured by arterial blood gas -- a much more accurate, but painful and invasive, procedure.

Sjoding says, is that pulse oximeters were three times as likely to miss significantly low oxygen levels -- or hypoxemia -- in Black patients.

Experienced physicians don't rely on the pulse oximeter alone to make a diagnosis or decide a patient's treatment, says Dr.

Gong says, during the pandemic, when hospitals are overwhelmed, and doctors who may not normally be in the emergency room are being brought in to see and triage patients, numbers from a pulse oximeter may hold more weight.

If a patient says they are having trouble breathing, physicians shouldn't dismiss them just because a pulse oximeter reading is normal.

The findings aren't new

Moran-Thomas uncovered studies going back to the 1990s that suggested there was a problem with pulse oximeters in darker-skinned patients.

In 2005, a study done at the University of California, San Francisco's Hypoxia Lab, found that three different models of pulse oximeters overestimated oxygen levels in dark-skinned patients.

The agency currently requires pulse oximeters to be tested on a variety of skin tones, meaning "at least 2 darkly pigmented (test subjects) or 15 % of the subject pool, whichever is larger."

The FDA says it is carefully reviewing the available data to determine whether additional guidance or studies from the agency are needed.

"Someone shouldn't overly rely on a pulse oximeter reading, even if it's the most accurate product."

"Just make sure you're aware of that when you're making decisions," says Dr.