A study out of the Harvard School of Public Health noted that some strains were harder to locate using a rapid test than others.
“The delta variant was more difficult to detect, it had a higher limit of detection than omicron. This may relate to the omicron subvariants because some of the strains of the omicron subvariant do have mutations in the gene that’s detected by the antigen test,” said Ph.D. candidate Sydney Stanley.
Source: False negative rapid Covid tests create confusion for people with obvious symptoms
