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Rapid Covid tests miss 90% of asymptomatic cases

nature.com

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Re: Rapid Covid tests miss 90% of asymptomatic cases

#231

Post by pama »

kbelder wrote: post #198
pama wrote: post #70

If anyone cares to increase the resolution of a rapid test, I recommend using Fiji and treating the image of the test strip like an antibody blot image and run the quantitative gel analysis (easy to find info on the web). The software integrates the signal along the direction of the strip, correcting for lighting conditions, and the resulting single curve can clarify a little bump well before (or after) the viral loa…

Isn't this just shifting the balance between false negatives and false positives?

To some degree yes, but these particular rehydrated antibody tests leave very little room for genuine false positives. If something binds on the test part of the strip it has the right epitope and there are no other viruses yet with these patterns. The integration of the signal across the width of the strip increases the signal to noise by a lot. I could detect decaying curves post infection at 50 times lower viral load than naked eye and confirmed by PCR. As the infection progressed, at some point the signal merges with the noise while PCR can still detect it, but the window is much smaller than with naked eye.

Re: Rapid Covid tests miss 90% of asymptomatic cases

#232

Post by blagie »

zoklet-enjoyer wrote: post #183
blagie wrote: post #151

Earlier quoted context omitted.

Why do you believe that?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10159620/

Edit: Additional thank you. That's a fascinating article and really well-written. I'm learning /a lot/ from it.

Re: Rapid Covid tests miss 90% of asymptomatic cases

#233

Post by mike_hearn »

tripletao wrote: post #220
mike_hearn wrote: post #201

Earlier quoted context omitted.

> test positivity has decreased from the peaks even as total test count plummeted. Where do you see that? Where I live that isn't the case and according to official data the pandemic has never ended: https://www.covid19.admin.ch/en/epidemiologic/test?epiRelDev... As recently as April the positivity ratio was as high as it was in December 2020 (~16%). I have no idea who these people are who get tested 10,000 times a w…

> Where do you see that? Where I live that isn't the case and according to official data the pandemic has never ended: If those data don't show the end of the pandemic, then what would? Your confirmed deaths are around 1/100 of the death peak. Positivity fluctuates much less, in part because there's a feedback loop--authorities will test more if it gets too high (subject to resource availability), and less if it gets…

It's probably best to leave it here, because you seem to just be arguing the position that I was describing ("If the PCR test correctly reports the presence of viral RNA ... then that's not a false positive").

This thread is sufficient to prove my point - the idea that PCR tests have very low or even zero false positive rates is essentially misinformation spread by scientists who are unwilling to consider anything about how the tests are actually used. Your whole post boils down to, "we only did PCR tests for statistical purposes so FPs didn't matter as long as they didn't affect the trend, if governments used them for other things well that has nothing to do with scientists".

Sorry, but like hundreds of millions of other people I simply don't accept this perspective. We don't think politicians had much agency because they just followed instructions from scientists at every point. Therefore the science community owns the COVID response. They don't get to now dissemble and engage in blame deflection when people point out what a catastrophe it was.

Re: Rapid Covid tests miss 90% of asymptomatic cases

#234

Post by mike_hearn »

Pyramus wrote: post #228
mike_hearn wrote: post #173

Earlier quoted context omitted.

I referenced the SAR in the post you're replying to (not under that name). Measuring that it's quite low isn't an explanation of why that happens, or an incorporation of that fact into policy. I get what you mean about consensus but scientific consensus is by definition clear cut, it's supposed to mean 100% agreement. Often something is presented as a scientific consensus when it's really not, rather, people who disa…

> Often something is presented as a scientific consensus > During COVID a lot of things were presented to the public as if it were 100% obvious and agreed with by every specialist Who is it that presents things to the public? Who are "they"? Who is "the media"? At least in the country I live in different journalists/writers/bloggers had very different opinions and they changed significantly over time. You could even…

"They" means scientists. The CDC, SAGE in the UK and the equivalents in other countries. They were directly giving briefings and press conferences.

We got to watch the scientific process in real time, indeed. It consisted of new evidence coming in and nobody updating their beliefs.

> If different countries had come to similar conclusions independently, that would mean the conclusion are likely valid, no?

No. After all, that cuts both ways. Many hundreds of millions of people around the world who were fully independent of the scientific grant funding structure watched this process and came to very different conclusions. So that must be mean the conclusions are likely invalid, no?

Re: Rapid Covid tests miss 90% of asymptomatic cases

#235

Post by tripletao »

mike_hearn wrote: post #227
tripletao wrote: post #222

Earlier quoted context omitted.

If he's not sick, then why should he take AZT? And if Typhoid Mary isn't sick, then why can't she work as a cook? The point is that even if you feel good now, a positive HIV test means that without treatment, you'll almost certainly die within the next 10-20 years. You can also infect others, and they'll die too. (As to the 14 years, the patient Mullis talked to was presumably some combination of lucky and/or benefit…

You're conflating asymptomatic with pre-symptomatic. The former means you never develop symptoms. The latter means you are about to get sick but aren't currently.

That HIV patient was indeed near-certain to be symptomatic later, but Typhoid Mary was permanently asymptomatic. That's unusual for typhoid, but for other pathogens (e.g. cytomegalovirus) most infected patients are permanently asymptomatic, with only a small minority of patients showing symptoms:

https://www.cdc.gov/cmv/congenital-infection.html

Your claims are inconsistent with at least a century of boring, uncontroversial medicine. I don't know whether you're doing it knowingly, but you're closely repeating the arguments of Kary Mullis, who was clearly smart (he invented PCR!) but not exactly reliable (he denied that HIV causes AIDS! he saw a talking, fluorescent raccoon!).

Re: Rapid Covid tests miss 90% of asymptomatic cases

#236

Post by tripletao »

mike_hearn wrote: post #233
tripletao wrote: post #220

Earlier quoted context omitted.

> Where do you see that? Where I live that isn't the case and according to official data the pandemic has never ended: If those data don't show the end of the pandemic, then what would? Your confirmed deaths are around 1/100 of the death peak. Positivity fluctuates much less, in part because there's a feedback loop--authorities will test more if it gets too high (subject to resource availability), and less if it gets…

It's probably best to leave it here, because you seem to just be arguing the position that I was describing ( "If the PCR test correctly reports the presence of viral RNA ... then that's not a false positive" ). This thread is sufficient to prove my point - the idea that PCR tests have very low or even zero false positive rates is essentially misinformation spread by scientists who are unwilling to consider anything…

> We don't think politicians had much agency because they just followed instructions from scientists at every point.

No matter what your desired policy, you could find a scientist to support it--some scientists were advocating for Chinese-style lockdowns, while others were drafting the Great Barrington Declaration. So how do you think the politicians chose which scientist to listen to, or to promote in the mass media? It's not like they took a poll--the vast majority of scientists expressed no policy opinion at all, and simply concentrated on their actual work.

Politicians are the ones with the power to make laws, and direct the police to enforce them, if necessary with physical violence. It's amazing to me that their attempt to cloak their policy decisions in "trust the science" worked so well on you that you've absolved the people with actual power of their actions, instead directing your anger at some abstract "scientists".

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