Need to measure skin tone accurately, to ensure the accuracy of Pulse Oximeters

Physicians and government regulators agree that pulse oximeters measure oxygen levels less accurately in patients with darker skin and need to be fixed.

Pulse oximeters can have some degree of bias based on a person’s skin tone. This is because the sensors in a pulse oximeter use light to measure the oxygen levels in a person’s blood, and the amount of light that is absorbed by the skin can vary depending on its color – as the light can be blocked by melanin in the skin. Due to this darker skin tones may absorb more light, which can make it more difficult for a pulse oximeter to accurately measure the oxygen saturation level in the blood. This can lead to inaccurate readings and potentially result in a lack of proper treatment for the patient.

To minimize this potential bias, some pulse oximeters are designed to automatically adjust the amount of light that is used in the measurement, based on the person’s skin tone. This has raised another challenge for scientists – how to measure skin tone correctly? The problem had been identified as early as 1990 by Amal Jubran, a pulmonologist at Loyola University Medical Center in Illinois. “It never got any traction, then the COVID pandemic brought everything to the forefront,” Jubran told USA TODAY.

A 2022 study by Jubran and a colleague published in the peer-reviewed European-Respiratory Journal found that inaccurate oximeter readings in darker-skinned patients remained “unchanged” for 32 years.

So far, the US Food and Drug Administration (FDA) is the only national regulatory authority to act decisively on this issue. In 2021, the FDA issued a Safety Communication on Pulse Oximeter Accuracy and Limitations and in 2022 announced a special meeting to discuss ongoing concerns that pulse oximeters may be less accurate in individuals with darker skin to guide further regulatory actions.

Other national and international health regulatory authorities have remained silent, including the World Health Organization (WHO), while just one pulse oximetry manufacturer, Masimo, has shared their own internal evaluation.

Until pulse oximeters are modified to work on all skin tones, patients should be made aware of this basic healthcare inequity that must be addressed to avoid potentially catastrophic consequences.