More Evidence Suggests Pulse Oximetry Fails People of Color

Featured Buzz – January 26, 2026

Hypoxemia is more often missed by pulse oximetry in patients with darker skin color, British researchers report, using data from a previous trial on various approaches to oxygen therapy to examine differences between pulse oximetry readings and arterial blood gas measures.

The study included 903 critically ill patients who were treated in 24 ICUs in the U.K. between June 2022 and August 2024. Five different oximeters were used to measure SpO2, and results from those devices were compared to SaO2 results from co-oximetry taken at the same time. The researchers determined how often SpO2 failed to detect hypoxemia by evaluating the false-positive and false-negative rates for SpO2 ≤92% and ≤94% relative to a reference SaO2 threshold of ≤92%.

A handheld spectrophotometer, which measures light reflection over different wavelengths, was used to ensure the objective measurement of skin tone. The authors believe this is one of the strengths of their study, as previous research in this area has either used race or ethnicity to stand in for skin tone or used skin tone charts or other color-comparison charts.

Overall, 11,018 pairs of SpO2 and SaO2 measurements were analyzed.

The researchers found:

• All five pulse oximeters overestimated at lower values of SaO2 and underestimated at higher values.
• On average, SpO2 readings were 0.6-1.5 percentage points higher for patients with darker skin tone than for those with lighter skin tone.
• At both SpO2 thresholds assessed, false-negative rates increased with darker skin tones; the proportion of SpO2 measurements >94% despite a paired SaO2 ≤92% was 5.3 to 35.3 percentage points higher for patients with darker skin tones than for those with lighter skin tones.
• By contrast, false positive rates decreased with darker skin tones.

The authors believe clinicians should use these results, along with those from other studies on this topic, to guide their interpretation of pulse oximetry in practice.

“The findings of our study and the work that preceded it need to be considered when determining the clinical relevance of SpO2 readings and steps taken to mitigate any potential harm that could occur by failing to appreciate the effect of skin tone on pulse oximetry accuracy,” they wrote. “SpO2 readings should be interpreted in the context of other clinical information and trends in SpO2 values given greater importance than single readings, particularly in patients with darker skin tones.”

The study was published by the British Medical Journal.