How Omicron Affects Testing for the Coronavirus

The rise of the omicron variant of the coronavirus has refocused attention on the importance of testing as a tool for bringing the pandemic under control -- and keeping it that way. At the same time, some tests used to identify infections may be less accurate detecting omicron cases.

The U.S. Food and Drug Administration has notified health care professionals of a handful of tests that, in the absence of modifications, are expected to fail to detect the variant or that were modified in order to pick it up. These are all so-called molecular tests, the gold-standard for diagnosing a coronavirus infection. The FDA said Dec. 28 that early data suggest that antigen tests -- which are faster, cheaper and more accessible -- detect omicron but possibly with reduced accuracy. A study posted Dec. 24 suggested that saliva samples may be better for diagnosing omicron than nasal specimens, whereas the opposite was true for delta, the variant that became the dominant strain worldwide in mid-2021.