Originally Posted by
gnaget
The antigen tests like Binax supposedly have ~100% specificity so should not produce a false positive. They do have variable sensitivity depending on viral load and whether you have symptoms, so could have false negatives, but that depends how you define a positive. PCR could make nearly any sample positive from someone who has ever crossed paths with the virus, depending on the cycle threshold. If you ask a tech running a test then they will have no idea about the cycle threshold. So I would always opt for the antigen test.
We plan to be tested in Denmark before departure, where there are test centers readily available for both Rapid Antigen and PCR tests. Some will provide a document that can be printed, others provide the information in an app that foreigners can use. They all claim to be EU compliant, but none of them will actually state they can be used for international travel, and that it is up to the traveler to ensure they get the right test for entry to whatever country is relevant.
I've also read the information on the US Embassy in Denmark website which provides a list of test centers, but specifically makes clear that this list is neither an endorsement nor confirmation that those tests will comply with the CDC requirements. They then merely refer to the CDC website. On the CDC site, it says a rapid test can be used provided it is "viral."
How can one really be sure that one gets the right test that is compliant? Perhaps I'm being overly concerned, but for example, one of the Danish websites with the list of test centers refers to the test being used to provide the "corona passport" for bars and restaurants (when that was a requirement, which it no longer is), so would that test be good enough for entry to the U.S.?
Based on your comment, I'm now leaning towards the antigen test, and also like that results are immediate vs. waiting a full day for results of the PCR test, but I don't want to turn up at the airport - especially once we're in FRA to board our U.S. bound flight - and find out the test is not valid, or that our documentation isn't sufficient. (I know I'm getting myself overly worked up, but want to be sure we are on that flight home!)