We're not wrong.

You can find any number of extremely well-qualified people saying PCR should not be used as a standalone diagnostic tool. Even the government's own guidance says that.

There is past history of pseudo-epidemics being created solely from PCR testing - google whooping cough pseudo-epidemic to find one very good example.

If the govt and its advisors were right, they would be making the case rather than pointedly ignoring any alternative views.

Exactly.
Take taking down anything that goes against the narrative of the government immediately raises suspicions. If you have nothing to hide then why be frightened of opposing opinions. Oppsostion have well founded arguments for their opinions using governments own data in many cases (;even if that data is suspect ) so how come the government wont stand up and debate with the opposition /sceptics.???

The case is not cut and dry. The problem on here is everyone wants everything binary, it either works or it doesn't when the truth is somewhere in-between.

That isn't to say the way the UK and others are using PCR aren't flawed but that's about how they use the data not the test itself.

A lot of people don't understand enough about PCR to judge either.

Can rtPCR tell us who is infected and infectious? No
Can rtPCR tell us who has been exposed? Yes

So rtPCR can provide a guide. What's more the way its *supposed* to be used in the standard tests is you're supposed to have symptoms.

Someone with symptoms AND testing positive is far more likely to actually have covid than someone without symptoms (they maybe just exposed). It provides a 2nd opinion/ confirmation of the symptoms and isn't used as a single diagnostic.

The problem here is they're using the test for surveillance such as key worker testing and so on which is outside the recommended scope for use.

Much is made about PCR cycles (cT). There's a common misconception that there's a magic number where every test "works" at and above which its "false".

This simply isn't the case, every brand of test and different assay produce slightly different levels of amplification per cycle so cT=30 on one test is not the same as a different brand and so on. The UK .gov document mentions it here ( https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/926410/Understanding_Cycle_Threshold__Ct__in_SARS-CoV-2_RT-PCR_.pdf )

Someone just beginning an infectious phase would need a higher cT than say someone who had JUST recovered, no longer infectious and shedding large amounts of viral fragments.
Another problem is although SARs2 is very stable mutation wise there are ~1000 or so lineages with slight changes. Some of these slight point mutations have been shown to effect cT by roughly 5 or so

What *should* have been done is each approved test run against actual viral cultures to establish a cT threshold for *that specific test* to use as a pass fail.
That to my knowledge has never been done and is our single biggest problem with rtPCR currently - its completely uncalibrated.

To get around that problem they've taken the easy option and running at cT >=40.
This is capable of detecting and amplifying almost unbelievably small amounts of RNA and detecting it because the method is so powerful.

Note this does NOT as claimed by some increase the risk of false positives, detecting colds, flu and so on. Its actually the opposite - the higher the cycles the more the RNA signal you're looking for is separated out from the noise.
This is nicely explained here:- https://virologydownunder.com/the-false-positive-pcr-problem-is-not-a-problem/ (note i disagree with quite a lot of the other things there such as hes not separating out viable virus vs just RNA present but his explanation of high cT is good, particularly the graph).

People also misunderstand a false positive. They are thinking a false positive is any test that comes out as positive that the person testing does not have an active infection.
This isn't true - as stated the test is looking for fragments of RNA, nothing more. Its perfectly possible to have some resting in your nose (but not infecting) or you've recovered etc and still test positive. That's not a false positive - the test is working correctly and detecting RNA.
The problem is RNA doesnt mean you're infected (see above).

Let's pick an example here. A family in a house, 2 parents and a child. Lets say a parent gets symptoms, gets tested and is positive - they likely have COVID.
Now someone tests the child, the child has no symptoms, the test returned RNA present (positive).
This does NOT mean the child is infected - they *could* be, but living in the same house its perfectly possible to get some viral RNA in the nose or throat that has failed to infect via mucosal immunity, T-cell and so on. Its these situations the test can let us down and be misleading.
Now if the child goes on to develop symptoms they probably are infected. If the don't we have no idea if the child (i) was infected by asymptomatic or (ii) never infected in the first place.

With a lab based PCR with many methods you can interrupt the procedure after various cycles and measure a fluorescence meaning you'd know which cT that RNA was first detected.
This indirectly would allow an estimate to viral load (higher viral load == higher chance of infected == fewer cycles needed for a detection but even then its not perfect, see the first paragraph at the top).

However, the way we're doing mass testing in bulk in many scenarios is a closed black box, its simply too time consuming to do it that way so samples are shoved in, run for the full number of cycles and only tested once at the end to get a pass fail. This method is fast but removes all the diagnostic ability we have to judge viral load and so on and this is a problem.

If there was a calibration done with a stop threshold, we'd have more of an idea but without it they're just lazily using "RNA == infection" which we know categorically is not true.

rtPCR given no other variables are changed (and we know they aren't) is a good way of measuring relative amounts of the virus in circulation (by measuring exposure), its an "ok" way of confirming an infection *if* combined with symptoms but its a poor way of deciding on an infection *without* symptoms which sadly is how a lot of it is currently being used.

In an ideal world we'd have a simple, rapid test for actual viral infections (likely antigen based) but we don't and there doesn't seem to be any real desire for someone to develop one.

So we have rtPCR which isn't great but also isn't totally useless. Some of the criticisms are valid, some of them are not valid and based on people not understanding the tests or how they work.
In an ideal world each PCR test would be calibrated with a cT against viral culture to set a more useful threshold (and i cant understand why that hasn't been done- id have thought it essential to get approval for use...).
Failing that we'd have the actual cT before a result reported with the test result to allow an assessment of the likelihood of infection....But we don't do that either.

There's no doubt a percentage of PCR positives are people who are not and were not infected but we really have no idea what that percentage is. We also have no idea of the actual number of asymptomatics for the same reason.

People become binary, either its all perfect or its all wrong and that simply isnt the case.

Full Disclosure:- my formal training was as a Medical Biochemist with dissertation on a respiratory disease. I have used PCR for a lot of lab work so know how it works ALTHOUGH it was 20 or so years ago where methods were almost all manual and much slower. The concepts remain unchanged though.

"Works or it doesn't " ?
I dont want one simple and I dont want to be treated any different by saying no I dont want it.
It's that simple to me.
I feel fine. I possibly had something mild( covid) in January this year maybe maybe not but I prefer to have the choice to say no thank you.