You are viewing a single comment's thread.

view the rest of the comments →

[–] AntiMarx 0 points 2 points (+2|-0) ago 

PCR isn't a test it just amplifies a designated compound, the test is then performed on the results of PCR process. The sample tested against is based on a sequence around 20 units long: SARS-COV2 genome contains around 30,000.

Because the sample is so small A) it is not representing the theoretical virus in full B) the small sequence range is [shared and present in] by other types of coronavirus and possibly other cells etc too.

Again, I am not putting these forward as scientific truth, but in this world we need to speculate and solve it ourselves it seems, so I'm willing to speak and be wrong in search of a better model. Any science ppl please chime in.

[–] AssumingControl 0 points 2 points (+2|-0) ago 

A friend of mine, who works in biochemistry and genetics, said the PCR test amplifies the signal of that part of the DNA which encodes for the spike proteins on the surface of the virus. She said, it's because these are the most conserved part, since they have to always be compatible to human lung cell surfaces which arguably don't change too much from generation to generation. I am not convinced that SARS CoV II signal will not have an overlap with the common cold (another corona virus) and others which have the same type of binding spike proteins, because they infect lung cells as well.

[–] Swiiirlyhunter 0 points 2 points (+2|-0) ago 

They run it 40 times. Anything after 30 is amplified to the point of junk.

[–] AssumingControl ago 

40 times refers to the number of duplication cycles during the Reaction. You first have a sample, wash it, purify it and add chemicals to multiply the DNA strands you are looking for. Since DNA is of very low concentration in the sample, you gotta make more of it to have detectable amounts in your end product. Each of the 40 cycles effectively doubles the amount of DNA, because during one cycle one strand of DNA gets split and the halves (mono-strands) are each completed using free bases which you added during preparation.

[–] AntiMarx ago 

So riddle me this, call it holocaust maths round two:

How long does preparing the samples take?

How long does cycling samples take?

How long does testing the result of PCR take?

How long does it take untrained workers to do 6 million of these?

TBH maybe this comnent needs its own thread...