The FDA's new 2025 draft guidance requires pulse oximeter validation studies to increase participant cohorts from 10 to 150, with at least 25% having dark skin and 30% of data points derived from darker-skinned individuals to reduce measurement bias, according to a recent perspective.

Researchers Lipnick, Ehie, Igaga, and Bicker evaluated the FDA's January 2025 draft guidance for pulse oximeters, which seeks to improve accuracy across diverse skin pigmentation. The update follows evidence of measurement bias in individuals with darker skin, an issue highlighted during the COVID-19 pandemic and linked to health disparities. The guidance introduces significant methodological changes, including increased study size, objective pigmentation assessment, and stricter performance metrics.

The new guidelines expand the minimum validation cohort from 10 to 150 participants, requiring at least 25% of subjects and 30% of data points to come from darker-skinned individuals. Unlike previous subjective classification methods, the FDA guidance recommends spectrophotometry-based measurement using the individual typology angle (ITA) as a melanin surrogate to improve accuracy. Devices must also meet a root mean square error threshold of less than 3% with a 2-sided 95% CI and demonstrate minimal bias of under 3.5% for oxygen saturations between 70% and 85% and under 1.5% for saturations between 85% and 100%.

The researchers identified several potential challenges with the new guidance. The increased study size could potentially limit market competition, leading to higher costs and reduced device accessibility. They suggest an alternative adaptive study design approach that would allow for smaller sample sizes with appropriate justification. Despite requiring transparent participant demographic reporting, the FDA still allows manufacturers to conduct their own verification studies, posing potential bias risks.

A key concern is the lack of real-world clinical validation. Laboratory-based studies often enhance perfusion through warming, which may not reflect actual clinical performance. Although the FDA now recommends reporting pulsatility amplitude, it does not ban artificial enhancement techniques that could mask disparities. The guidance also continues to rely too much on subjective methods for skin pigmentation classification, specifying an objective definition only for the darkest half of the "dark" cohort.

While the inclusion of a performance reporting website and improved labeling requirements are positive steps, the researchers suggest additional transparency measures, such as standardized on-device labeling with FDA clearance designation and QR codes linking to performance data. They note that the guidance addresses only medical pulse oximeters, leaving challenges for users of non-FDA-cleared devices in homecare or resource-variable communities.

Though the guidance marks significant progress in addressing pulse oximeter disparities, the authors emphasize that refinements are necessary to avoid unintended consequences. They note the draft guidance remains open for public comment until March 10, 2025, and is not legally enforceable but may impact liability for non-compliant devices. The researchers conclude that complementary efforts across sectors, including clinician education on optimal SpO₂ use in clinical decision-making, will be crucial to improving patient care.

Complete disclosures for all authors can be found in the published perspective.

Reference: 

Lipnick MS, Ehie O, Igaga EN, Bicker P. Pulse oximetry and skin pigmentation—new guidance from the FDA. JAMA. Published online March 5, 2025. doi:10.1001/jama.2025.1959