NCHR urges FDA to require more diversity in trials to improve accuracy of pulse ox devices

December 2, 2022 Thank you for the opportunity to speak today on behalf of the National Center for Health Research. I am Dr. Ealena Callender, an OB/GYN with a master’s in public health. I am a Senior Fellow at a nonprofit think tank. Our center conducts, analyzes, and scrutinizes research on a range of health […]

The post NCHR urges FDA to require more diversity in trials to improve accuracy of pulse ox devices appeared first on National Center for Health Research.

December 2, 2022

Thank you for the opportunity to speak today on behalf of the National Center for Health Research. I am Dr. Ealena Callender, an OB/GYN with a master’s in public health. I am a Senior Fellow at a nonprofit think tank. Our center conducts, analyzes, and scrutinizes research on a range of health issues, with particular focus on which prevention strategies and treatments are most effective for which patients and consumers. We do not accept funding from companies that make products that are the subject of our work, so we have no conflicts of interest.

Thank you for convening this important meeting to discuss the critical issue of how skin pigmentation impacts the accuracy of pulse oximetry. The pulse oximeter is ubiquitous in medical care in the United States. Like blood pressure and respiratory rate, pulse ox is a vital sign used to make critical medical decisions. The accuracy of this device on all patients is of paramount importance.

Although skin pigmentation was thoughtfully considered when this technology was first invented, pulse oximeters in use today are dramatically different from the original “gold standard” device. In early studies, researchers considered many patient-specific variables, including skin pigmentation, that would contribute to pulse oximetry measurement¹. To accommodate these differences, the original device was standardized for each patient and provided accurate measurements for every individual¹.

Furthermore, early pulse oximeters used eight wavelengths of light, which was considered enough to account for individual patient variations. But today’s devices use only two^1,2.

There is now strong evidence that commonly-used pulse oximeters are less reliable for patients with pigmented skin. The inaccuracies related to skin pigmentation vary based on the device used. While one device may be inaccurate for pulse ox measurements under 90%, others may have significant inaccuracies at all ranges³. In general, inaccuracies related to skin pigmentation increased as the level of oxygenation decreased. Clinically, this means sicker patients are less likely to get an accurate reading from a pulse oximeter and are, therefore, less likely to get appropriate care.

The FDA has designed a study to evaluate pulse oximeter performance in hospitalized adult patients of different skin pigmentation levels. This is an important step. But we urge the FDA to do more.

Currently, the agency only requires pre-market testing to include at least two darkly pigmented individuals or 15% of the subject pool⁴. This is woefully inadequate. We ask you to urge the FDA to require that manufacturers include individuals with a broad range of skin pigmentations in their studies.

Moreover, subjective measurements of skin pigmentation are of little value because there is such wide variation in hues and so many contributing factors. Therefore, only objective tools for assessment of skin pigmentation should be used in studies of how it effects pulse oximetry measurements.

The FDA’s current guidelines do not require product labeling to address the impact of skin pigmentation on pulse oximetry. While labeling is important to alert users to possible inaccuracies, it does not diminish the importance of developing devices that are effective for everyone.

Medical devices must work effectively in all people, regardless of skin pigmentation. Products that are allowed on the market should not be accurate for only some races and ethnicities. The FDA should require more scrutiny to minimize bias in medical devices, so they are accurate and reliable for everyone.

1.     Merrick EB, Hayes TJ. Continuous, Non-Invasive Measurements of Arterial Blood Oxygen Levels. Hewlett-Packard Journal. 1976;28(2):20.
2.     Nitzan M, Romem A, Koppel R. Pulse oximetry: fundamentals and technology update. MDER. Published online July 2014:231. doi:10.2147/MDER.S47319
3.     Bickler PE, Feiner JR, Severinghaus JW. Effects of Skin Pigmentation on Pulse Oximeter Accuracy at Low Saturation. Anesthesiology. 2005;102(4):715-719. doi:10.1097/00000542-200504000-00004
4.     United States Department of Health and Human Services, Food and Drug Administration, Center for Devices and Radiological Health, et al. Pulse Oximeters-Premarket Notification Submissions [510(k)s]: Guidance for Industry and Food and Drug Administration Staff. Food and Drug Administration; 2013:16. Accessed October 26, 2022. https://www.fda.gov/media/72470/download

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