Pulse Oximeter Readings Shift From High to Low, Study Finds Worse Accuracy for Patients of Color

October 6, 2026 - 15:29

A new investigation into hospital pulse oximeter performance has revealed a troubling pattern: devices that once tended to read blood oxygen levels too high are now frequently reading them too low. Researchers say the shift raises fresh questions about how clinicians rely on these fingertip monitors when making treatment decisions.

The study examined readings from hospitalized patients and compared the device estimates against arterial blood gas measurements, which are considered the gold standard. In earlier periods, pulse oximeters often overstated oxygen saturation, meaning patients appeared healthier than they were. That bias could delay recognition of low oxygen and postpone necessary care. In the more recent data, the error moved in the opposite direction. The monitors increasingly understated oxygen levels, which can lead to unnecessary tests, overtreatment, or alarm fatigue among staff.

The inaccuracies were not evenly distributed. Patients of color experienced larger discrepancies between the device reading and the true blood oxygen level. The gap persisted across both the overestimating and underestimating phases, suggesting the problem is not a simple calibration drift but something tied to how the technology interacts with skin pigmentation and other physiological factors.

Researchers stress that pulse oximeters remain valuable tools for continuous monitoring. However, they warn that clinicians should confirm suspicious readings with blood gas tests when the result could change care. The findings add pressure on manufacturers to improve sensor design and on hospitals to track device accuracy by patient population.