Re: [DIYbio] DIY COVID-19 PCR test

tl, dr; if you get a DIY positive result I think that's useful, if it's negative then assuming everything else is equal you're in no different position to everyone else who hasn't been tested.

danger of the very likely false negatives

Yes, I absolutely agree Jonathan; false negatives are a problem.  With the use of a positive control plasmid Derek mentioned you can reduce some of the sources of false negatives such as completely incorrect or damaged primers, wrong temperatures for annealing or elongation, correct temperatures but faulty hardware, contamination of reagents with DNA nucleases (doesn't help with RNA specific nucleases), non functional polymerase, not adding NTPs, otherwise faulty master mix, not loading the gel correctly (assuming not using rtPCR), not reading it correctly, not running it correctly, not using the correct buffers, contamination with DNA nucleases, etc.  You can't correct for false negative error from inadequate DNA extraction protocol, not following extraction protocol, RNA specific nuclease contamination, non matching primers for different strain, etc.

Successful DNA extraction from samples and PCR in DIY settings though have and are performed.  I would not trust a negative DIY result if I had symptoms or reason to believe I was infected, but I definitely would not assume I was free from the virus if I had a positive result but no symptoms or reason to believe I was infected.

This is based on the assumption that the rate of false positives is small and that false negatives are the main source of error.  If you do get a negative then I think you're no worse off and are back to where you were before; do you disagree?  I've tried to explore what we might do differently given different DIY results (please add your comments or edit as you wish), assuming again that you're even moderately sure false positives are minimised because otherwise I think there's very little point in doing it in the first place.

Cheers,

AJP

On Wednesday, March 4, 2020 at 5:56:33 PM UTC, Jonathan Cline wrote:

On 3/4/20, AJP <bio...@gmail.com> wrote:
> I'd like to be able to test myself.

Great. Except for the danger of the very likely false negatives.


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