Pulse Oximeters Undercount Sleep Apnea in Black Patients

If you are Black and have sleep apnea, oxygen-based severity scores may understate your breathing events, so ask your doctor what else was measured.

Updated on Nov. 4, 2026 in Sleep Disorders

Bold flat-color editorial illustration of a gray finger-clip pulse oximeter with a red light emitter resting on a pale cream surface, evoking a medical measurement gap. — A Mass General Brigham study found pulse oximeters undercount sleep apnea breathing events in Black patients, potentially understating disease severity in those scores. AI Illustration. Upload story photo >

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Pulse oximeters, the finger clips used to measure blood oxygen, appear to undercount sleep apnea breathing events in Black patients, according to a study published by Mass General Brigham investigators. The bias produced oxygen-based severity scores that did not track cardiovascular events or death in Black participants, unlike heart-rate-based scores.

Why it matters

Sleep apnea severity scores guide decisions about diagnosis and treatment, so a measurement gap that falls along racial lines could mean some Black patients are assessed as less severely affected than they are. The finding adds to earlier documentation of pulse oximetry racial bias in other settings, including Covid-19 care, but until now its reach into sleep apnea scoring was not known.

The study analyzed data from two independent cohorts, MESA and SHHS, comparing oxygen-based and heart-rate-based sleep apnea severity scores. The 21% and 20% differences in MESA and SHHS, respectively, were the key racial gaps, and the researchers found oxygen-based severity measures were not significantly associated with cardiovascular events or death in Black participants.

The players

Mass General Brigham

A major Boston-based academic health system whose investigators conducted the study and whose clinicians treat sleep disorders across its hospitals.

The details

Pulse oximeters emit light through a part of the body and measure how much is absorbed, which is how they estimate blood oxygen levels. Melanin and other pigments in darker skin can absorb some of that emitted light, which can distort the reading. Because sleep apnea scoring in this study relied on a standard 4% oxygen-desaturation threshold, the distortion lowered the count of events that met the criterion in Black participants.

November 4, 2026: Mass General Brigham published the study findings in a news release.

Health Landscape

Pulse oximetry racial bias was documented in Covid-19 patients before this study, raising questions about the device's reliability across clinical settings. This research carries that concern into sleep medicine, where severity scores shape diagnosis and treatment decisions.

If you are a Black adult who has been evaluated for sleep apnea, the findings are worth raising with your sleep physician, especially if your oxygen-based readings seem inconsistent with symptoms. Ask whether heart-rate-based or airflow-based measures were also considered when your severity was assessed.

The takeaway

Pulse oximetry readings may understate sleep apnea events in Black patients, so oxygen-based scores alone may not capture severity accurately for everyone. If you have concerns about how your sleep apnea was measured, a conversation with your sleep specialist about the full picture of your symptoms and test results is a sensible next step.