Pulse Oximeters: FDA drafts guidance to address performance disparities

The US Food and Drug Administration (FDA) has proposed guidance on developing pulse oximeters primarily used in hospital settings or doctors' offices to address differences in the effectiveness of the products depending on the patient's skin tone. The agency wants pulse oximeter sponsors to provide more data that better reflects the intended patient population and ensure the product labels clearly state their limitations.

While there was evidence even before the COVID-19 pandemic that many pulse oximeters used to determine patient oxygen levels did not work as well in some people, the pandemic highlighted racial disparities in the accuracy of such products after darker-skinned patients received delayed treatment due to inaccurate readings.

FDA is trying to address the issue by asking manufacturers to consider how skin tone may affect their products' performance in the new draft guidance. The guidance follows multiple advisory committee meetings and a 2023 discussion paper on the topic.

"This draft guidance is aligned with the FDA's broader commitment to helping facilitate the development of high-quality, safe, and effective medical devices," said Michelle Tarver, director of the FDA's Center for Devices and Radiological Health (CDRH). "Our draft recommendations are based on the best available science to help address concerns of disparate performance of pulse oximeters based on an individual's skin pigmentation."

“The updated draft recommendations are aimed at helping generate a more representative study of the intended population for these devices,” said FDA. “The FDA believes the implementation of these recommendations, if finalized, will help improve the accuracy and performance of pulse oximeters used for medical purposes in patients across the range of skin pigmentation.”

In the draft guidance, FDA has proposed that sponsors should collect clinical data from sources such as controlled desaturation laboratory studies and real-world data (RWD) to assess the accuracy of their pulse oximeters across a range of skin pigmentations. The agency also wants sponsors to include more study participants to reflect the intended patient population better and use subjective and objective methods to evaluate their product.

Specifically, FDA recommended sponsors use the Monk Skin Tone (MST) scale as a subjective method to categorize the skin tone of study participants when evaluating how their pulse oximeter performs. The guidance includes an appendix on MST, and the agency recommends printing out the MST scale on calibrated printers and verifying it using calibrated spectrophotometers before using it in clinical studies.

“The FDA expects some pulse oximeters that are currently marketed may meet the updated performance criteria without the need for significant hardware or software modifications,” said FDA. “In these instances, if a sponsor submits updated labeling to reflect the collection of clinical data that demonstrates comparable performance across skin pigmentations without device modifications, other than changes in labeling, then the FDA generally intends to review the submission expeditiously (within 30 days) to help ensure the public has prompt access to safe and accurate pulse oximeters.”

Another important aspect of the proposed guidance is ensuring that the product label clearly states the pulse oximeter's limitations depending on the patient’s skin tone. FDA has proposed different labeling requirements for prescription devices and over-the-counter (OTC) devices. The agency noted that prescription devices may be exempt from having adequate directions for use if they meet certain requirements. On the other hand, OTC devices must include adequate directions for use and information such as all the conditions, purposes, or uses the device is intended for and clearly state their limitations.

"Accurate, clear device labeling can help mitigate performance issues associated with pulse oximeters and is important to make users aware of the risks, limitations, and directions for use of pulse oximeters," said FDA. "Moreover, a device shall be deemed misbranded if, among other things: its labeling is false or misleading; its labeling does not contain adequate warnings; or any information required to be in the labeling is not prominently placed with such conspicuousness and in such terms to render it likely to be read and understood by the ordinary individual."

"As always, FDA will make case-by-case decisions regarding the enforcement of legal requirements in response to particular circumstances and questions that arise regarding a specific device," the agency added. "This may include FDA requesting a firm initiate a recall … or taking other actions, including an enforcement action."

The draft guidance includes an appendix that provides an example of labeling that can be used for a marketed pulse oximeter with potential warnings and directions for use that satisfy FDA’s requirements.

While most of the pulse oximeters affected by the proposed guidance are intended for use in hospitals and doctors’ offices, FDA noted that some are currently available as OTC products. The agency further stated that the guidance would not apply to pulse oximeters sold as general wellness or sporting and aviation products.

FDA has proposed publishing a publicly available website that lists all FDA-cleared pulse oximeters to help patients and healthcare providers better identify which products have undergone review.

Stakeholders can comment on the draft guidance on www.regulations.gov under docket no. FDA-2023-N-4976 until 10 March.

Draft guidance

Pulse Oximeters: FDA drafts guidance to address performance disparities

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