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Two months after Democratic lawmakers expressed concern about potential racial disparities in pulse oximeter readings — calling the issue a matter of “life or death” — the Food and Drug Administration on Friday issued a public warning about the devices, acknowledging they had “limitations.”

The alert comes decades after researchers first identified potential inaccuracies with the devices when used on people of color and months after a series of new studies produced fresh data underlining the problem. Most recently, researchers at the University of Michigan published a December 2020 letter in the New England Journal of Medicine that found oximeters were nearly three times as likely to miss hypoxemia in Black patients compared with white patients.

“Be aware that 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 FDA’s alert reads.


It does not explicitly mention racial disparities in the accuracy of the devices, likely disappointing clinicians and patients who have sought to draw attention to the issue.

“It’s noticeable that the word ‘race’ or ‘racial’ is not mentioned in the FDA communication,” said Thomas Valley, a pulmonary critical care physician and an author of the NEJM letter. “At the same time, what we found was a difference between Black and white patients. We don’t know exactly why that difference existed, we presume it to be skin tone.”


Pulse oximeters, which measure oxygen levels, have emerged as a particularly useful clinical tool amid the Covid-19 pandemic because of the way the virus interferes with the body’s natural ability to process oxygen. In hospitals, the devices play a critical role in making decisions about patient care. And late last spring, after several practitioners suggested the devices could be helpful to have on hand at home (similar to the way one might want to keep a thermometer in the drug cabinet, for example), at-home versions of the devices began flying off drugstore shelves and rapidly selling out on Amazon and other online sites.

But the December paper — and its reference to a series of earlier studies documenting the same problem, including one published in 2005 — raised alarms among researchers and clinicians, who said they were frustrated to learn the issue had not been addressed in a substantive way after 15 years.

“To not be confident in the accuracy of that number, and to depend on a device that may have bias toward a certain population is really troubling,” Utibe Essien, a physician and an assistant professor of medicine at the University of Pittsburgh School of Medicine, told STAT earlier this month.

In response to these concerns, William Maisel, director of the Office of Product Evaluation and Quality at the FDA’s Center for Devices and Radiological Health, told STAT the agency was reviewing the available data and would consider further studies if necessary. He said the FDA is broadly confident that hospital-based oximeters are highly accurate, but added the same might not be true for devices sold online and in drugstores, which the agency doesn’t review or approve.

Michael Sjoding, a pulmonary physician at Michigan Medicine and an author on the NEJM letter, said he was happy the FDA stressed the importance of not over-relying on pulse oximeters to make medical decisions in its statement. He added, though, that he thought the absence of an explicit mention of race was a “missed opportunity.” 

“Given the limitations of our paper … I suspect the FDA wants to be fairly guarded in their messaging about racial disparities in pulse oximeter accuracy and focus more on the problem of pulse oximeter inaccuracy more generally,” he said.

  • Statnews, are we doing child labor now ? Biology and Physics are taught in classes above elementary grade but it seems non of the authors of this article knows Biology and Physics.

    It is good that the author edited the article from “body producing oxygen” to “body processing oxygen” as suggested by one commenters.

    Light are block/absorb by pigments. The color you see from pigments are the color reflected by pigments. Therefore is you see black, that means non of the primary color in the color spectrum where reflected. White, all colors are reflected. Oximeters operates on light, therefore very much affected by things that block/absorb light.

    It seems the authors of this article have not taken Biology and Physics yet so they must only have received elementary education. Since mid and high school are mandatory where Biology and Physics are taught, one can help thinking if we are doing child labor here making elementary level children write this article. Did we get the consent of the parents ?

  • Finger oxymetry uses infrared light to detect oxygen saturation as oxygenated hemoglobin absorbs more infra-red light. SO : with light-based detection, the device is less effective for darker-skinned people. This has been know for over 20 years – but nothing has been done to adapt. The FDA should state this clearly, which could provoke R&D for (finger) oxymetry that DOES work better for darker skinned people. “Racial Bias” in the title of this article is a very colored expression for a very transparent flaw (puns intended).

  • Author, shame on you for trying to add more to race divide. Your article lower the quality of statnews. But then you are not alone in statnews doing that. Maybe the quality of statnews is going downhill.

    When you cry “wolf” you desensitize people.

  • When does this crazy everything is racial stuff from the Liberals stop? A racist oximeter? Just like racist covid-19. Liberalism is a dangerous mental disease. And no, Liberals are certainly not racist. They treat everyone equal; they hate everybody legally in America.

  • Oximeters uses beam of light to measure the oxygen. If you have anythings blocking light such as pigments, nail polish, etc, then the light beams will be affected. A little bit of common sense instead of doing racial bias intrigues.

    The ignorant doctor who made a comments about racial bias is plain stupid. The law of physics is blind to race and is govern by law of physics. It seems he was sleeping in class when the professor / teach was teaching basic of light propagation, diffraction, absorptions. I wouldn’t want a stupid doctor like him to treat me.

    The author should do much research of how oximeters works instead of doing the racial bait intrigues.

    • Does the degree of one’s skin and nail bed melanation play a PHYSIOLOGICAL role in light absorption and transmittable ? I recall a recent article in the NEJM ( New England Journal of Medicine) that raised this as a question. As a science oriented individual and practicing physician I WELCOME opinions that consider any and all perspectives and insights that may HELP in my evaluation of my patient (s). I for one, would CONSIDER the POSSIBILITY of a pulse oximeter reading being affected by the degree or intensity of melanin in the skin and nails. That’s biology and physics !!
      This is further illustrated in the absorption of UV light through the skin and how it affects the production and metabolism of Vitamin D in the skin. Melanin does in fact DECREASE the absorption of UVB light into the skin ! This is important to know and understand.

      Not all science is “racist ” ! We should be very careful not to draw errant conclusions unless and until we’ve read, researched and studied the SCIENCE !

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