[techdevangelist]

What is the expectation people will actually get the swab far enough back to collect a meaningful sample? Having been on the receiving end of a nasal collected flu test, it was a pretty deep probing. I’m kind of doubtful most people can do it to themself properly without some prompting to ‘go deeper’.

[jacobriis]

You only need to swab the edge of your nostril for this test.

https://www.pixel.labcorp.com/covid-19-sample-collection

[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.

[James_Henry]

There's evidence that for Covid-19 it's not necessary to go as far back as people have been going. There's also evidence that self-collection works well. The FDA has acknowledged this before and allowed self-collection with physician oversight before they allowed this test.

[MikeAmelung]

Where is this evidence? How does this square with the evidence that RT-PCR tests are already coming back falsely negative, probably due to missing the virus while swabbing? Pardon me for being skeptical, but this is all from the same people who have bungled this every step of the way.

[cbhl]

I'm having trouble finding the actual study, but UnitedHealth Group, working with the Bill & Melinda Gates Foundation, Quest Diagnostics, and the University of Washington did a study on the efficacy of self-swabbing.

https://techcrunch.com/2020/03/25/study-behind-updated-fda-g...

[James_Henry]

I found the paper. I haven't read through it so I can't say if it is actually any good, but it is good enough that the FDA changed their recommendations because of it (that might not mean much, of course).

https://www.medrxiv.org/content/10.1101/2020.04.01.20050005v...

[MikeAmelung]

Thanks for tracking it down. Doesn't seem to be any problem with accepting their results that it's almost as good as a nasopharyngeal swab, so you won't see me complaining about it again.

[takeda]

Not really an evidence, but looks like their instructions explicitly say to not insert it deep: https://www.pixel.labcorp.com/covid-19-sample-collection

[biased_coin]

Prompting to 'go deeper' could potentially be done over a video call. I hope LabCorp does some sort of beta testing to know how well people do with instructions.

[James_Henry]

https://www.fda.gov/medical-devices/emergency-situations-med...

The FDA doesn't think it is necessary to go that deep.

[throwaway55554]

Put a mark on the swab, put a rubber band around the mark on the swab and say it has to go back that far. Have a test for adults and another for children.

But, the video from the actual labcorp website someone else posted shows it does not actually have to go very deep.

[edoceo]

Even adult noses are different sizes, the depth is a relative measure.

[LatteLazy]

I think they're just assuming you will pay 119USD (Plus tax and shipping) for a box because coronavirus. What you do with it after your transaction clears really isn't their concern...