FDA Issues Draft Guidance for Improving Skin Tone Disparities of Pulse Oximeters

Fingertip pulse oximeters are getting a rethink from the US Food and Drug Administration. In a draft guidance document issued on January 6, the agency outlined the steps it is taking to improve the accuracy and generalizability of the devices across diverse patient populations.

The FDA says the public comment period for the recommendations will be open until March 10, 2025.

In 2021, FDA issued a safety communication describing the limitations of over-the-counter and prescription pulse oximeters and highlighting factors that can affect their accuracy. These include poor circulation, skin thickness, skin temperature, valvular disease, high ambient light, current tobacco use, fingernail polish, artificial nails, tattoo ink on fingers, and skin pigmentation. Following that, an advisory committee meeting was held, followed by another in 2024. The executive summaries of both explained ongoing concerns that the devices are not accurate across all skin tones and reviewed adverse events that have been reported in real-world patients due to inaccurate readings.

Additionally, in a 2023 discussion paper asking for feedback, the FDA concluded that the COVID-19 pandemic had increased the general public’s use of pulse oximeters and zeroed in on the need to account for skin-tone differences and broaden performance testing in premarket studies.

The new draft guidance includes recommendations for manufacturers on how to gather clinical data, among other things, to help improve the clinical study design and validation efforts, including expectations for pulse oximeters that were previously cleared for use. One recommendation focused on premarket sample size studies advises including 150 participants representing diverse skin pigmentation, up from just 10 people in prior recommendations, and conducting pairs testing across ranges of oxygen saturation values. Useability testing also is recommended to identify potential use error and help mitigate sources of user error.

With regard to labeling, the FDA says if a manufacturer submits clinical data showing nondisparate performance, they can include a prominent statement on the package labeling and package insert indicating that it has been evaluated to perform comparably across groups of individuals with a wide variety of skin tones. They also recommend that the labeling indicate all conditions, purposes, or uses for the device.

The FDA further recommends that manufacturers “prominently display appropriate warnings in the instructions for use regarding how to avoid known hazards and/or be aware of certain relevant risk or safety information associated with the use of the pulse oximeter.” These warnings may include statements such as:

• Differences in skin pigmentation may cause differences in pulse oximeter sensor performance and thereby impact readings, especially in very low oxygen levels
• Trends in measurement may be more meaningful than one single measurement
• Not all blood oxygenation values have been verified with clinical performance testing

Other suggested instructions would offer advice for lay users on fluctuating values as well as when to seek medical attention for values outside of normal range.

The document further clarifies issues related to skin tone differences, detailing correct positioning of the device on the finger during clinical testing to capture skin pigmentation variations, how to evaluate forehead pigmentation of study participants through visual assessment with the Monk Skin Tone scale, and how to document information related to diversity in race and ethnicity of study participants.