Pulse oximeters are one of the most widely used tools in hospitals to measure a patient’s oxygen levels without needing an invasive procedure. For the majority of patients, the device works well, offering quick and accurate readings that help doctors assess the need for oxygen therapy. However, there is a significant issue with the accuracy of pulse oximeters for patients with darker skin tones, especially Black patients, a problem that has gone largely unaddressed until recently. This flaw in medical technology is not just a minor inconvenience it could be a matter of life and death for many.
Take the case of Tomisa Starr, a 61-year-old woman from Sacramento, California. Starr, who lives with chronic health conditions such as heart failure, was admitted to the hospital for a blood pressure spike. Despite her long history of needing supplemental oxygen, her request was denied during her hospitalization. Why? The pulse oximeter, a device placed on her finger to measure her oxygen levels, gave a misleadingly high reading. This reading suggested that her oxygen levels were normal, despite the fact that she was struggling to breathe. Starr, who is Black, tried to explain to her care team that research had shown that pulse oximeters may not work as accurately on people with darker skin, but her concerns were dismissed with skepticism.
Starr’s experience is not unique. Dr. Hugh Cassiere, a critical care physician at South Shore University Hospital in New York, has often encountered similar reactions from healthcare professionals. “This device has built-in racial disparities that have been ignored for years,” he says. Despite knowing about the issue, medical professionals have been slow to act, and pulse oximeters have remained in widespread use without adequate testing for their effectiveness across skin tones. It wasn’t until the COVID-19 pandemic that the full extent of the problem became apparent.
As the pandemic unfolded, doctors like Dr. Thomas Valley at the University of Michigan began noticing that pulse oximeters were providing false readings, especially among Black patients. In severe cases of COVID-19, these false readings could lead to underestimating the severity of a patient’s oxygen deprivation, resulting in delayed treatments that worsened their conditions. Dr. Valley and his team published their findings in the New England Journal of Medicine in December 2020, which helped bring national attention to the racial biases inherent in pulse oximeter technology.
For years, the issue had been largely ignored, despite studies as early as 1989 highlighting the potential inaccuracies of pulse oximeters on individuals with darker skin. Yet, it took the mounting health crisis of a global pandemic for the medical community to start taking action. In 2021, the FDA issued a warning, acknowledging that pulse oximeters can be less accurate for people with darker skin tones. This led to the drafting of new guidelines to ensure that device manufacturers test their products on a diverse range of skin tones before releasing them to the market.
Pulse oximeters work by shining a light through the skin to measure the amount of oxygen in the blood. The device relies on the absorption of light by oxygen-rich blood, with the idea that the more light absorbed, the better. However, this method is flawed when applied to individuals with more melanin in their skin. Melanin absorbs more light, which can lead to falsely high oxygen saturation readings for Black and brown individuals, masking the severity of their condition.
While the FDA has taken steps to address this issue by urging manufacturers to include people with diverse skin tones in their testing, the problem is far from solved. Some devices still perform poorly on individuals with darker skin, and the reasons for this discrepancy remain unclear. Researchers at the University of California, San Francisco, are conducting studies to understand why certain pulse oximeters perform better than others across different skin tones. However, it may be years before a comprehensive understanding of the issue emerges.
The delay in solving this problem is particularly frustrating for healthcare professionals who treat predominantly Black and brown patients. Dr. Noha Aboelata, who works at Roots Community Health in Oakland, California, expressed frustration at the slow response to addressing the issue. “How could we possibly have a medical device that only works well on white skin?” she said. This is why some clinics, like Roots Community Health, have even taken legal action against manufacturers to push for changes in how pulse oximeters are made and tested.
The truth is that pulse oximeters have a fundamental flaw that could be putting Black patients, in particular, at significant risk. Doctors and patients alike need to be aware of this issue to avoid misdiagnoses and delayed treatments. For now, patients like Tomisa Starr continue to rely on pulse oximeters, despite knowing that the results may not be entirely accurate. The hope is that the FDA’s new guidelines will lead to more equitable medical devices, ensuring that all patients, regardless of skin tone, receive the proper care they deserve.