Pulse oximetry is used to triage patients, initiate or adjust oxygen administration, and, more recently, as a way to remotely monitor COVID-19 patients at home. However, a study in the Johns Hopkins Health System showed that Asian, Black, or Hispanic patients are more likely to experience inaccurate readings, potentially resulting in missed or delayed diagnosis of respiratory diseases. This study used paired oxygen saturation by pulse oximetry and arterial oxygen saturation in arterial blood gas in Black and white patients before and during the COVID-19 pandemic. Consistent with the Johns Hopkins study, Black patients had three times the frequency of occult hypoxia than white patients.