Devices that monitor blood oxygen levels in the hospital and at home need to be more carefully regulated, a Food and Drug Administration advisory panel indicated at a meeting Tuesday.

The devices are everywhere in healthcare settings, and people regularly purchase them for at-home use. But research over the past few decades has steadily shown that they don’t work as well for people with darker skin tones — a disparity that became even more critical during the covid pandemic. The FDA issued an alert saying that the devices have “limitations” in 2021.

“We need to take appropriate steps to remove the growing uncertainty around these devices and ensure the health and safety of the public,” anesthesiologist Jesse Ehrenfeld said to the panel this week.

The devices, called pulse oximeters, generally fall into one of two categories: prescription devices used at hospitals and doctors’ offices; and over-the-counter devices that are used for “general wellness.” The prescription devices have to go through clinical testing before they’re sold — but only on a small number of people. The over-the-counter devices aren’t reviewed by the FDA before they’re put on the market.

The panel reviewed multiple research studies that show oximeters don’t work as well on darker skin. Those inaccuracies can have real consequences for patients: it delayed covid treatments in Black patients because the devices didn’t show dropping oxygen levels, according to one study from May.

The meeting focused on prescription devices, but the panel was also concerned about the over-the-counter “wellness” devices. Categorizing something as a wellness product lets companies sidestep regulatory scrutiny and sell something to consumers as long as they don’t claim that the product they’re selling can diagnose or treat a medical condition. But people use pulse oximeters they buy online or from pharmacies to monitor conditions like covid regardless.

“These are not health and wellness items. This is not a toy,” said Murad Alam, vice chair of the department of dermatology at Northwestern University, during the panel meeting.

The panel floated a few ideas to make people aware of the risks, including putting them behind the counter or adding warning labels.

The FDA panel didn’t hold any votes or make any formal recommendations at the meeting Tuesday. But the discussion around over-the-counter devices is likely of interest to companies making smartwatches that have blood oxygen features — like Apple and Fitbit. Neither took the feature through the FDA process, so both fall under the “wellness” category. If the agency were to make any changes to over-the-counter blood oxygen monitors, they’d be affected.