Clinicians should be aware that pulse oximeters may have “suboptimal accuracy” in patients with darker skin pigmentation, according to the Centers for Disease Control and Prevention.

Pulse oximetry has been used widely during the pandemic to assess and monitor COVID-19 patients’ oxygenation status, which can be a key marker of the respiratory disease’s severity. But a number of studies over the years have suggested that the devices weren’t well-vetted in people with dark skin.

“Limited data from studies with small numbers of participants suggest that skin pigmentation can affect pulse oximeter accuracy,” the CDC noted Tuesday (Feb. 16) in updated clinical guidance for COVID-19 patient management. 

The agency cited a recent study of intensive care patients that found that the devices were unable to detect hypoxemia — or low blood oxygen levels — nearly three times more frequently in Black patients than in white patients.

“Given the widespread use of pulse oximetry for medical decision making, these findings have some major implications,” the study’s authors wrote in a December 2020 issue of The New England Journal of Medicine.

The CDC appears to concur. The resulting questions raised about the devices’ efficacy highlight the importance of assessing other factors, it said. These would include high-risk conditions and observed signs and symptoms “rather than relying on pulse oximetry measurement alone when assessing, triaging, and managing patients with suspected or laboratory-confirmed COVID-19,” the agency concluded.