> Well false positive is quite self explanatory, false positive as in "the test returned a false positive result"
No it certainly isn’t. Positve for what? Presence of the virus? Then the PCR test is highly accurate. It is testing for a series of nucleotides that would be virtually impossible to occur randomly in your body. It is testing for long strands of rna that are highly improbable to occur anywhere else in nature.
But maybe we don’t care whether someone has a trace amount of virus. Probability of infection (replication) and consequently contagiousness is what we really care about. These scientists are pointing out that people with low amounts of the virus are unlikely to get the illness or spread it.
Thats what the inventor of the PCR test is pointing out.
You need to additional samples from people who only test positive at 35 cycles, and monitor whether their viral load increases and whether they get symptoms.
That way you can give people their probability of developing or spreading covid with positive results.
>No it certainly isn’t.
Yes, it is
>Positve for what? Presence of the virus?
Well duh... Being tested positive for covid19 doesn't mean "good news you don't have it"...
>Then the PCR test is highly accurate.
Its inventor said the exact opposite, especially when it comes to anything above 35 cycles with it "with PCR, if you do it well, you can find almost anything in anybody." And, commenting on cycle thresholds, once said: "If you have to go more than 40 cycles to amplify a single-copy gene, there is something seriously wrong with your PCR.”
The PCR does not test for Covid 19. Covid 19 is a disease— COrona VIrus Disease 19— which is caused by the SARS-CoV 2 virus when it replicates inside your body.
Definition is important. What are you actually measuring?
The number of virions (individual virus) you inhale will largely determine whether you get sick. You can inhale hundreds or thousands of virions and not get covid infection. The probability of infection goes up with the amount of virus you are exposed to.
If they test for 30 nucleotides in a row (they probably test for several segments this long in the PCR) the number of permutations is 430 which is around 1 SEXTILLION.
There are about 6 billion base pairs in the human genome so the number of possible strands of mRNA 30 nucleotides long that could possible “show up” would be less than 6 billion.
1 sextillion/6 billion is roughly 200 million.
1 in 200 million
The chance that this sequence would randomly show up in a person should be considerably less than that. That would be if human genome was really random from person to person, which it isn’t.
You cant just root around in people long enough an find a 1 in sextillion sequence.
The issue is trace amounts of virus unlikely to cause infection are leading to positive PCRs and erroneous case counts.
>The PCR does not test for Covid 19.
PCR tests are used to diagnose covid19
https://www.health.harvard.edu/blog/which-test-is-best-for-covid-19-2020081020734
Diagnostic tests for current infection
If you want to know if you are currently infected with the COVID-19 virus, there are two types of tests: molecular tests and antigen testing.
Molecular tests (also called PCR tests, viral RNA tests, nucleic acid tests)
How is it done? Nasal swabs, throat swabs, and tests of saliva or other bodily fluids.
Where can you get this test? At a hospital, in a medical office, in your car, or even at home (the FDA recently granted EUA for a home molecular test that requires no prescription).
What does the test look for? Molecular tests look for genetic material that comes only from the virus.
....
(post is archived)