3 ms·
> A large anti body study was supposed to be released yesterday, and I'm waiting to see what it says. Also be aware that there are false positives, especially
by acqq 7y ago
> A large anti body study was supposed to be released yesterday, and I'm waiting to see what it says.
Also be aware that there are false positives, especially significant with these antibody tests, so with the low numbers of positives it's extremely important to evaluate if the claimed values are more than noise artifacts of the tests themselves. It is also important to be aware of the scenarios for which the use of the apparent test results is not reasonable.
Moreover, here's what happened in the UK a few weeks ago:
https://www.theguardian.com/world/2020/apr/09/uk-government-urged-to-abandon-poor-finger-prick-antibody-tests-coronavirus https://www.theguardian.com/world/2020/apr/09/uk-government-...
"None of 3.5m home tests ordered have so far been accurate enough to detect coronavirus immunity"
UK got 3.5 million(!) unusable antibody tests.
https://www.bmj.com/content/369/bmj.m1449 https://www.bmj.com/content/369/bmj.m1449
"John Newton, Public Health England’s director of health improvement, said:"
"A number of companies were offering us these quick antibody tests, and we were hoping that they’d be fit for purpose, but when they got to test, they all worked but were just not good enough to rely on.
“The judgment was made [that] it’s worth taking the time to develop a better antibody test before rolling it out, and that is what the current plan is.”"
"Newton told the committee that the tests trialled so far had lacked sufficient sensitivity to identify people who had been infected. “We set a clear target for tests to achieve, and none of them frankly were close.”"
- nchie 7y agoAre you sure there are false positives with the serological tests they're using? As far as I've read, there are tests with only false negatives, and if I don't misremember they were the ones used for the Swedish statistical study released (and retracted) last week.
- acqq 7y ago> Swedish statistical study released (and retracted) last week I don't know any details about that specific study, or why it was retracted etc, so any links to more info appreciated! I was writing about the general problems existing when there are little actual positives, and also about the known or maybe somewhere less mentioned issues.
- SiempreViernes 7y agoRumour tells me the problems were mostly related to unaccounted selection bias of the test group, not the lab methods used.
- nchie 7y agoI've only read about it in Swedish, but here's [1] a Reddit post discussing it in English (with the top-comment referencing a later news article which says the study was retracted). 1: https://www.reddit.com/r/COVID19/comments/g4znbg/at_least_11_of_tested_blood_donors_in_stockholm/ https://www.reddit.com/r/COVID19/comments/g4znbg/at_least_11...
- acqq 7y agoThanks. Automatically translated highlights of: https://www.svt.se/nyheter/inrikes/nya-antikroppstestet-baserat-pa-osakert-underlag https://www.svt.se/nyheter/inrikes/nya-antikroppstestet-base... "Uncertain conclusions of the new antibody test -- Updated April 22, 2020 Published April 21, 2020" "The assignment was presented in yesterday's News by Jan Albert, professor of clinical microbiology and chief physician. Now the researchers are withdrawing the report - because it may be based on uncertain evidence." "The study already used existing tests from healthy blood donors as a basis. The preliminary results showed that 11 out of 100 bar on antibodies to the coronavirus in Stockholm. Today, the group behind the research has gone out with information that this is not true - they have used unsafe evidence." "Thus, there may be fewer than 11 out of 100 infected, but how many can not say until they have done the study. In the coming weeks, they will start over from the beginning. The tests already done will be scrapped."