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Grant's May 2022 Update
I've not tested positive.
what's your standing on covid tests? There's 2 types of them where I live, PCR in labs & antigenic, which can be done in a pharmacy or some tent in 15 minutes. Especially the antigenic, I wonder how technologically it is possible to find something which cannot be seen in microscope in those conditions and timings.
The genomes used as primers in the covid PCR tests are derived from computer constructed genetic material, not from genetic sequences pulled from isolated virus. Do a search for 'Sars-Cov-2 insilico genome'. Highly suspect.
The PCR tests are generally overly sensitive to everything and are much more likely to give false positives (saying you have Covid when you don't) than false negatives. They work by amplifying trace amounts of substances, so my understanding is that, even if you just have some non-active fragment of SARS-COV-2 that happens to get on the swab (for example, it's lodged in your nasal passages but isn't capable of replicating), then that fragment would get amplified into a visible "signal" and suggest that you have active Covid.
You can think of PCR tests as being highly conservative - they are very unlikely to miss someone who has Covid, but they are also highly likely to give false positives (when using the currently CDC-recommended number of cycles in the amplification process).
I'm not as familiar with the antigen tests, but it sounds like they are kind of at the other end of the spectrum as the PCR test. Because the amount of antigen present in the test in large part depends on the amount of viral activity/load in the tested area, you could get a false negative at the beginning of an infection when there is a low level of viral activity that is still building. If you get a positive on the antigen test, it is much more likely that you actually have active Covid than with a positive on the PCR.
One potential solution to these flaws in the testing is to use multiple types of testing simultaneously, but that costs more money, takes more time, and probably causes more confusion to the average person. Really, people should only be testing when they're symptomatic, otherwise you're just asking for false positives, especially from PCR.
Quote from wavygravygadzooks on May 7, 2022, 12:55 pmThe PCR tests are generally overly sensitive to everything and are much more likely to give false positives (saying you have Covid when you don't) than false negatives. They work by amplifying trace amounts of substances, so my understanding is that, even if you just have some non-active fragment of SARS-COV-2 that happens to get on the swab (for example, it's lodged in your nasal passages but isn't capable of replicating), then that fragment would get amplified into a visible "signal" and suggest that you have active Covid.
You can think of PCR tests as being highly conservative - they are very unlikely to miss someone who has Covid, but they are also highly likely to give false positives (when using the currently CDC-recommended number of cycles in the amplification process).
I'm not as familiar with the antigen tests, but it sounds like they are kind of at the other end of the spectrum as the PCR test. Because the amount of antigen present in the test in large part depends on the amount of viral activity/load in the tested area, you could get a false negative at the beginning of an infection when there is a low level of viral activity that is still building. If you get a positive on the antigen test, it is much more likely that you actually have active Covid than with a positive on the PCR.
One potential solution to these flaws in the testing is to use multiple types of testing simultaneously, but that costs more money, takes more time, and probably causes more confusion to the average person. Really, people should only be testing when they're symptomatic, otherwise you're just asking for false positives, especially from PCR.
Ultimately any indirect test like a PCR or antibody/antigen test is only as good as its gold standard. It's the only way you can assess the tests' sensitivity and specificities. To do that you have to isolate the item you're testing for. The term 'isolation' has been highly bastardized in modern virology such that it's all smoke and mirrors.
ok thanks. Where I live (France) it was used somewhat in the contrary way, people first tested antigen, and then if positive, PCR to confirm.
Supposedly antigen gave more false positives than PCR.
I have briefly read about PCR principles and discovery, and failed to understand how this technology can be used to diagnose something. Heck, if I'm not wrong even it's inventor said that it shouldn't be used to diagnose, or at least in isolation. To add to this confusion, here for covid PCR was used differently if tested in a city lab or in a hospital lab, the number of "cycles" was quite different so depending on where the test was done it could be positive or negative.
To sum it up, when I face so much contradiction, non-sense etc, coming from a position of authority, with a rhetoric of "it's like that and nothing else" my natural common sense is to reject this "science" altogether.
Huh, that's the first time I've ever heard in silico (pseudo-latin derived from the true latin phrases in vitro, in vivo, in situ). Apparently it was coined all the way back in the 80's when computers were first becoming more widespread. Made me laugh as soon as I realized it was a modernized latin knock-off.
In Silico essentially just means that something is being digitally manipulated. In the case of viruses, it looks like it's being used for phylogenetics in order to figure out the likely evolutionary history of different viruses and their variants and to identify their geographic origins.
There's nothing "sketchy" about this. It's not like they just made up the genome of SARS-COV-2 from scratch on a computer...they are taking the entire genomes of different samples of SARS-COV-2 that have been sequenced by conventional sequencing methods, and comparing them to one another on a computer, using models to sort out the most likely evolutionary histories. Because we don't have access to every single link in an evolutionary chain for a virus or organism, we have to use models to identify the possible intermediary steps based on the subset of real world samples that we do have access to. This is one method of interpolation.
Yes, your confusion and response to that particular confusion about Covid testing is unfortunately very common and is why I said that the Covid pandemic has totally destroyed the average person's trust in science. It's not "science" that is at fault though, it is the people who are in charge and making policies that they claim are based on sound science.
All the idiots in charge are to blame, particularly governing organizations and the WHO. The testing for Covid is terribly inaccurate, particularly the PCR. And you are correct in saying that the "inventor" of PCR does not condone its use for diagnosing disease, and has spoken out against it. PCR is not a good diagnostic tool and was never intended for that purpose. This is plainly obvious when you look at the different number of cycles used in the amplification process. The more cycles used, the more false positives. The fewer cycles used, the more false negatives. If there was a good balancing point, they should have stuck to it from the beginning, but instead different groups/labs have been using different cycle thresholds (CTs) which makes the results from these PCR tests completely inconsistent and therefore useless.