Oxygen-monitoring devices may be less reliable in Black patients, researchers say

Covid-19, the disease caused by the novel coronavirus, can cause blood oxygen levels to fall to dangerously low levels, and devices used to monitor these levels are far less reliable in Black patients than in White patients, a large study found.

Pulse oximeters clip onto a fingertip and pass red and infrared light through the skin to gauge oxygen levels in the blood, which darkens when levels drop. Because pulse oximeters were mostly tested on Whites when they were developed, they are calibrated for people with light skin. Among 1,609 patients studied last year at the University of Michigan Hospital in Ann Arbor, the devices missed low oxygen levels in 11.7 percent of Black patients compared to 3.6 percent of White patients.