We also don’t yet know at what point during the course of illness a test becomes positive… you will get a false negative test result [on a swab test] 100% of the time on the day you are exposed to the virus. (There are so few viral particles in your nose or saliva so soon after infection that the test cannot detect them.)… About 40% of the time if you are tested four days after exposure to the virus
So this sounds like, with a smear or swab or saliva test, you’d want to wait up to 4 days after potential exposure, and a false negative remains possible.
I believe I’ve seen elsewhere that the saliva test is comparable to a swab in accuracy, but is more foolproof (because you don’t have to take a sample from your throat).
According to Harvard //www.health.harvard.edu/diseases-and-conditions/if-youve-been-exposed-to-the-coronavirus
So this sounds like, with a smear or swab or saliva test, you’d want to wait up to 4 days after potential exposure, and a false negative remains possible.
I believe I’ve seen elsewhere that the saliva test is comparable to a swab in accuracy, but is more foolproof (because you don’t have to take a sample from your throat).