Hugh Cassiere, MD, South Shore University Hospital at Northwell Health.

Hugh Cassiere, MD

Racial Bias in Pulse Oximetry Skews Sleep Apnea Diagnoses, Warns Hugh Cassiere, MD 

 SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies

, on Wednesday, June 11th, in Seattle, Hugh Cassiere, MD, a specialist in pulmonary internal medicine and critical care from South Shore University Hospital at Northwell Health in New York, presented on racial bias in pulse oximetry.

sat down with Cassiere at the conference to discuss how the inaccuracy of pulse oximetry across minority groups poses challenges in 

 Pulse oximetry was invented in 1974, and 16 years later, in 1990, the physician Martin J. Tobin, MD, FCCP, published an article that said patients on mechanical ventilatory support who were darkly pigmented had 2 and a half times the inaccuracies on the pulse oximeter compared with White patients.2

“In other words, they could have a normal pulse oximeter, yet when you tested their blood for their oxygen level, they were deficient,” Cassiere explained.

Although it has been 35 years since Tobin reported pulse oximetry inaccuracies, not much was done about these discrepancies until the pandemic. The industry was not sure whether they should really worry about these inaccuracies, if they even posed clinical issues. But the pandemic raised the importance of an accurate pulse oximeter reading.

COVID-19 can develop into acute respiratory distress syndrome, a life-threatening disease that causes low oxygen muscles. Pulse oximetry helps monitor the respiratory status of patients with COVID-19, but patients with darker skin can get a false reading, putting their health at risk.

Patients with darker skin may have COLT hypoxemia, where you could have a pulse oximetry saturation of 92 to 96%, but according to a blood test, an oxygen saturation of < 88%, which is low.

Pulse oximetry readings are important when it comes to diagnosing sleep apnea, as it is diagnosed by having a pulse oximeter on the finger while sleeping. The number of obstructions or desaturations observed will categorize patients as having mild or moderate sleep apnea.

“One of the worries is that if you have pigmented skin, these desaturations may not be so paramount,” Cassiere said. “So maybe you won't be diagnosed with sleep barrier, and even if you are diagnosed with sleep apnea, maybe the desaturations are underestimating your severity.”

A relevant disclosure for Cassiere is Masimo Corporation.

Cheng J, Cassiere H, Gurubhagavatula I, et al. Pulse Oximetry in Sleep Medicine: Addressing Racial Bias and Improving Equity. Presented at SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies, on Wednesday, June 11th, in Seattle.

Jubran A, Tobin MJ. Reliability of pulse oximetry in titrating supplemental oxygen therapy in ventilator-dependent patients. 

. 1990;97(6):1420-1425. doi:10.1378/chest.97.6.1420

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At SLEEP 2025, Cassiere discussed how pulse oximetry inaccuracies among patients with darker skin tones may lead to underdiagnosis or misclassification of sleep apnea severity.

Hugh Cassiere, MD

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