[clumsysmurf]

It was my understanding, that its easy to get false negatives with this kind of test because the virus moves down the respiratory track as time goes on. Too early, its not sensitive enough. Too late, nothing there. It has to be in a specific window of opportunity. Can somebody jump in and correct me if I am wrong?

[cypherpunks01]

It does move down the respiratory tract, but nasal epithelial tissue can still contain/produce the virus for awhile even after it "moves". For me, I was able to physically feel the inflammation move down from my throat to lungs to abdomen, but that was 5 weeks ago, and I just tested positive on a deep nose swab rtPCR given yesterday. A lot of people are testing positive for surprisingly long time.

I wouldn't be surprised if a light nasal swab like being discussed here doesn't pick up anything post-symptoms, whereas PCR with the deep nasal swab may still be detectable for a longer time after primary symptoms have faded.

[fspeech]

It is now thought that the virus can also infect cells in the nose. Cough and nasal discharge could also bring virus from deeper parts of the body to the nasal passage.