Levitan says that use of home finger pulse oximeters by patients with COVID-19 could preempt the precipitous oxygen desaturation that leads to a crisis that needs intensive care.

Clipped over a fingertip, pulse oximeters determine a person’s blood-oxygen level by shining light through the skin and measuring its absorption by the blood.

The Food and Drug Administration approves the type of fingertip pulse oximeter used in hospitals and sold by prescription. The agency issued a safety communication about the flaws in early 2021.

Nonin introduced the fingertip pulse oximeter in 1995. This year it has shipped the devices to hospital and clinics throughout the United States and to 140 countries.