COVID-19 antigen test sensitivity could be as low as 60% with omicron: FDA

A single antigen test may only be able to correctly identify the virus 60% of the time in patients who have the omicron variant and who display symptoms of the disease, Tim Stenzel, director of the Food and Drug Administration’s Office of In Vitro Diagnostics and Radiological Health, said during a Wednesday meeting on testing. 

The FDA is seeing an increase in samples with the omicron variant that have a relatively low viral load, also referred to as a low positive. “Instead of seeing the usual 10% to 20% low positives in clinical studies last year, we saw a jump to 30% to 40% low positives,” Stenzel said. “When you have 40% low positives… you’re going to see a really big hit in sensitivity.”