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FDA Proposes Overhaul of Pulse Oximeter Testing to Reflect All Skin Tones

• By John K. Waters
• 01/06/2025

The humble pulse oximeter, a fingertip device that became an essential tool during the COVID-19 pandemic, is under scrutiny. For years, doctors have known it doesn’t perform as well on patients with darker skin tones. Now, the U.S. Food and Drug Administration (FDA) is proposing new guidelines to fix the problem—but critics say the plan still doesn’t go far enough.

Pulse oximeters measure blood oxygen levels by shining red and infrared light through the skin. The device calculates oxygen saturation by analyzing how the light is absorbed. But studies have shown the device often overestimates oxygen levels in non-white patients, leading to real-world consequences during the pandemic. Some patients with darker skin were denied critical care, missed out on supplemental oxygen, and even suffered higher rates of organ failure and death.

Under the proposed FDA guidelines, pulse oximeter manufacturers must test devices on at least 150 people from a diverse range of skin tones, using the Monk Skin Tone Scale—a tool that categorizes skin into 10 shades. At least 25% of participants in each study must represent light, medium, and dark skin tones, with half of the dark-skinned group including individuals with very dark skin.

This is a sharp departure from previous guidance, which required testing on just 10 subjects, only two of whom needed to be “darkly pigmented.” The FDA is also recommending device labels include a statement if the oximeter has been proven to work equally well across all skin tones.

The FDA’s guidance encourages manufacturers to use real-world data from sick patients, but experts say collecting such data is expensive and complex. Some argue that without mandatory testing on hospitalized patients, the guidelines fall short.

Some companies are already taking action on the new guidelines. Medtronic, a major pulse oximeter manufacturer, said it has already begun using the Monk Skin Tone Scale in device testing. “We’re deeply committed to equitable care,” the company said in a statement.

The FDA’s proposal includes creating a public list of devices that meet the new standards. As public comments roll in over the next 60 days, one thing is clear: the debate over equitable medical technology is far from over.