The accuracy of a COVID-19 antigen test depends on various factors such as the sensitivity and specificity of the test, the quality of the sample collected, and the timing of the test in relation to the onset of symptoms or exposure to the virus.
In general, antigen tests are less accurate than PCR tests, which are currently considered the gold standard for COVID-19 diagnosis. Antigen tests may have a higher rate of false negatives (meaning a person who has the virus tests negative) and a lower rate of false positives (meaning a person who does not have the virus tests positive).
However, the accuracy of antigen tests has improved over time with the development of newer and more sensitive tests. According to the U.S. Food and Drug Administration (FDA), some antigen tests have shown sensitivity levels of up to 95%, depending on the manufacturer and the type of test used.
It's important to note that antigen tests are generally recommended for people who are symptomatic or who have had close contact with someone who has tested positive for COVID-19. A negative result on an antigen test does not completely rule out COVID-19, and confirmatory testing may be necessary if a person has symptoms or a known exposure.