Pulse oximeters overestimate oxygen saturation in patients with darker skin

Incident

Pulse oximeters overestimate oxygen saturation in patients with darker skin

17 December 2020United States (University of Michigan and 178-hospital cohort; Johns Hopkins COVID-19 cohort)Study findingDevices Models & agents

Paired SpO2/SaO2 data showed occult hypoxemia missed by pulse oximetry about three times as often in Black as in White patients, delaying treatment decisions.

Sources checked when written 26 September 2026

What happened

Sjoding and colleagues compared pulse oximetry with arterial blood gas measurements. Occult hypoxemia (SaO2 below 88% while SpO2 read 92-96%) occurred in 11.7% of measurements in Black patients vs 3.6% in White patients at Michigan, and 17.0% vs 6.2% in a multicenter cohort. A 2022 Johns Hopkins COVID-19 study found SpO2 overestimated SaO2 by 1.1-1.7 points in Asian, Black and Hispanic patients relative to White patients, and Black patients had a 29% lower hazard of being recognized as eligible for oxygen-threshold therapies. FDA issued a safety communication in February 2021, held advisory panels in November 2022 and February 2024, and issued draft guidance on 7 January 2025 revising performance testing across skin pigmentation. As of this review FDA's product page still lists the January 2025 guidance as draft.^[1,2,3,4]

Documented harm

Documented delayed or missed recognition of treatment eligibility (Fawzy 2022); individual patient outcomes not attributed.

What it teaches

A device that keeps reporting a plausible wrong number triggers no downtime procedure at all.
Validation populations define who the device is accurate for; ask for the data by skin tone.
Thresholds built on a biased sensor (triage, therapy eligibility, early-warning scores) inherit the bias.

Sources

Racial Bias in Pulse Oximetry Measurement. New England Journal of Medicine (Sjoding MW, Dickson RP, Iwashyna TJ, Gay SE, Valley TS), 17 December 2020. Primary Peer-reviewed · link checked 2026-09-26
Racial and Ethnic Discrepancy in Pulse Oximetry and Delayed Identification of Treatment Eligibility Among Patients With COVID-19. JAMA Internal Medicine (Fawzy A, et al.), 1 July 2022. Primary Peer-reviewed · link checked 2026-09-26
Pulse Oximeters (FDA actions on accuracy and skin pigmentation). U.S. Food and Drug Administration, 6 January 2025. Primary Guidance · link checked 2026-09-26
Pulse Oximeters for Medical Purposes - Non-Clinical and Clinical Performance Testing, Labeling, and Premarket Submission Recommendations (Draft Guidance). U.S. Food and Drug Administration, 7 January 2025. Primary Guidance · link checked 2026-09-26

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