Same day as the Centers for Disease Control and Prevention relaxed COVID-19 guidelinesthe Food and Drug Administration issued a statement warning that rapid home antigen tests can give false negative results and that people who need tests should plan to have them more than once to ensure they are ‘not unknowingly spreading the SARS virus -CoV-2 to others”.
Health experts recommend testing for people who have been exposed to the virus or are showing symptoms.
“Today’s recommendations are based on the latest results from studies of people who may be infected with Omicron, showing that repeat testing after a negative COVID-19 home antigen test result increases the chance to obtain an accurate result,” the FDA said in a safety communication released Thursday.
Previously, the FDA had advised people to perform two rapid antigen tests over two or three days to rule out an infection.
These recommendations, the FDA said, are based on data from a depth study conducted in collaboration with the National Institutes of Health (NIH) and the University of Massachusetts Chan Medical School, which has shown that this testing method repeatedly reduces the risk of negative results. The study reportedly included more than 7,000 participants.
In the warning, the agency said antigen tests, also known as home COVID-19 tests, are less accurate than molecular tests, such as polymerase chain reaction (PCR) tests. This means that taking a home test too soon, after being exposed to COVID-19, could lead to a false negative result, particularly if a person has no symptoms.
The FDA is now advising people who plan to use home tests to get more than one so they can test more than once. For people with symptoms of COVID-19 who test at home and receive a negative result, the agency recommends taking a second COVID-19 home test, 48 hours after the first, for a total of at least two tests. .
“If you test negative on the second test and are concerned that you have COVID-19, you can choose to test again 48 hours after the second test, consider having a molecular lab test, or call your health department . supplier,” the FDA said.
For those who suspect exposure to COVID-19 but have no symptoms, the FDA now recommends up to three tests, each separated by a 48-hour period.
If a person tests positive at home initially or after repeating a test, the agency stressed that it likely means a person has COVID-19 and that they “should follow CDC guidelines for those with of COVID-19”.
Health specialists warned that testing too early can lead to false negative results. For those who have been exposed to COVID-19, centers for disease control and prevention recommends waiting at least five days after being exposed to COVID-19 before taking an antigen test. The reason for this is that it can take several days for these home tests to detect an infection.
The FDA also said people don’t need to stick to a specific test brand and can use tests from different manufacturers each time for this repeat testing approach. A list of all FDA-authorized home tests and more information about COVID-19 home testing can be found here. found here.