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New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

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Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#221

Post by whatshisface »

adatavizguy wrote: post #209
aeonsky wrote: post #171

Earlier quoted context omitted.

I'm sure you are aware of story behind Theranos - doing complex tests on a drop of blood is currently impossible.

Would there have been a path of honesty at Theranos such that they would thrive in the age of covid-19?

That's like asking, "could Enron have been an honest energy company..." sure, with a different board, different executives, different strategy, different technology, different IP, different market sector, and if they sold ice cream cones for fair prices at the local pool.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#222

Post by trehalose »

whatshisface wrote: post #220

> Alternative index value thresholds for positivity resulted in 100% sensitivity and 100% specificity in this cohort. This would be true of a coin flip, wouldn't it? "Head means positive, tails means not negative" would be 100% sensitivity and "Tails means negative, heads means you're not positive" would be 100% specificity. So those would be the "alternative index value thresholds." https://en.wikipedia.org/wiki/Sen…

You misunderstand. A test that labels everyone positive would be 100% sensitivity but 0% specificity, and a test that labels everyone negative would be 100% specificity but 0% sensitivity. Deciding every case at once by a single coin flip would thus be useless.

As the article says, "A perfect predictor would be described as 100% sensitive, meaning all sick individuals are correctly identified as sick, and 100% specific, meaning no healthy individuals are incorrectly identified as sick." Deciding every case at once with a single coin flip does not meet both critera of a perfect predictor.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#223

Post by whatshisface »

trehalose wrote: post #222
whatshisface wrote: post #220

> Alternative index value thresholds for positivity resulted in 100% sensitivity and 100% specificity in this cohort. This would be true of a coin flip, wouldn't it? "Head means positive, tails means not negative" would be 100% sensitivity and "Tails means negative, heads means you're not positive" would be 100% specificity. So those would be the "alternative index value thresholds." https://en.wikipedia.org/wiki/Sen…

You misunderstand. A test that labels everyone positive would be 100% sensitivity but 0% specificity, and a test that labels everyone negative would be 100% specificity but 0% sensitivity. Deciding every case at once by a single coin flip would thus be useless. As the article says, "A perfect predictor would be described as 100% sensitive, meaning all sick individuals are correctly identified as sick, and 100% specif…

Not at the same time, but it does if you split it in to two separate tests, each with an "Alternative index value threshold."

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#224

Post by zaroth »

Animats wrote: post #133

This is encouraging. Two negative viral tests and a positive antibody test, and people should be able to get an ID that says they're exempt from movement and mask restrictions. (To discourage faking this, getting that ID should also turn eligibility for the Emergency Care Benefit, since they can work safely.) There's still argument over how long immunity lasts, but it has to be at least two or three months, or there…

> A special document to exempt people from “movement and mask restrictions”...

I just find this idea viscerally revolting. All I can think of is armbands with the Star of David.

I don’t believe there can ever be any justification for mass restriction of movement in society, because such is a roadmap for tyranny.

However I need only make the case there clearly isn’t justifiable ends in our current pandemic. What we have found is a minuscule and highly stratified extreme-risk population (mostly, nursing homes) and a vast majority for which COVID is the least of their concerns. Much more pressing a concern for the masses is getting back to their jobs, their so-called “elective” procedures, and resuming healthy socialization and recreation patterns.

What we need, and what the Constitution requires are strictly targeted measures to keep COVID out of nursing homes, and for everything else to re-open.

Mass restriction of movement and mandatory testing is neither legal, nor is it conscionable.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#225

Post by bb2018 »

kbenson wrote: post #211
docbrown wrote: post #188

Earlier quoted context omitted.

> I still think there's a possibility this virus was already in the US before 2020. Yeah, I don’t understand why people are so against the idea of it being in the U.S. before 2020. There’s no possible way we can trace every American who may have traveled within the China region or interacted with another person who was in that region around the start of COVID spreading. Just because there were no official cases of CO…

I think the main evidence against it being here siginifgantly earlier is that we see how it spread when it was definitely here, so why wouldn't we have seen hot spots like Atlanta and New York earlier then?

Yeah - if someone could point me to a nursing home where 5% of the population died in a week in December/January I'd believe it - anecdotes about people being having the flu in the winter isn't the most convincing.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#226

Post by docbrown »

bb2018 wrote: post #225
kbenson wrote: post #211

Earlier quoted context omitted.

I think the main evidence against it being here siginifgantly earlier is that we see how it spread when it was definitely here, so why wouldn't we have seen hot spots like Atlanta and New York earlier then?

Yeah - if someone could point me to a nursing home where 5% of the population died in a week in December/January I'd believe it - anecdotes about people being having the flu in the winter isn't the most convincing.

> if someone could point me to a nursing home where 5% of the population died in a week

Sure, if we were talking about mortality rates but we’re not. we’re simply talking about prevalence of COVID prior to the major breakout of February and beyond. These are two completely different things to be looking at.

I’ve worked in nursing homes during that time of December where people were dying. Did we think to send bloodwork off to test for some novel coronavirus? Of course not. Secondly, using the example of a nursing home as the sample population is silly as they are not the ones who were traveling. It’d be their family members and caregivers who traveled and then brought the disease into the facility.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#227

Post by bb2018 »

docbrown wrote: post #226
bb2018 wrote: post #225

Earlier quoted context omitted.

Yeah - if someone could point me to a nursing home where 5% of the population died in a week in December/January I'd believe it - anecdotes about people being having the flu in the winter isn't the most convincing.

> if someone could point me to a nursing home where 5% of the population died in a week Sure, if we were talking about mortality rates but we’re not. we’re simply talking about prevalence of COVID prior to the major breakout of February and beyond. These are two completely different things to be looking at. I’ve worked in nursing homes during that time of December where people were dying. Did we think to send bloodwo…

I think you are missing the statistical point I and others are making. If the disease was introduced in a meaningful way in December/January it would be a statistical certainty we would see signs of it (such as nursing homes having huge waves of deaths or total mortality in subregions surging).

I'm not sure what your counterclaim is? There are no samples in America tested from that time period that would show that there was Covid nor is there any statistical evidence that would suggest there was Covid.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#228

Post by tcbawo »

jrockway wrote: post #83
y-c-o-m-b wrote: post #75

Earlier quoted context omitted.

"Weird cold" in February checking in. I did not have any temperature variations or fevers, but I got struck with a fatigue like no other. For the first time since I was 3 years old, I took afternoon naps three days in a row because I was just completely wiped out. It's rare for me to take a nap at all (happens maybe once a year)! It took two weeks to get out of this fatigued state. My other symptoms were "chills-like…

I agree with you on being open to thinking that COVID-19 arrived earlier than was initially thought. When I first shared my "weird cold" story on HN, the consensus was that I was a crazy person and there was no way that could be COVID-19. There would be more deaths if it had been here. But now there are some deaths, and a large number of people with "weird cold" stories, and it really makes me think that a lot of peo…

A lot of the opinion I've read suggests that so called super-spreaders are seeding the majority of flare-ups. In other words, there may be some individuals with very high R0 compared to the vast majority of others. My theory is that Covid-19 was circulating for some time here until the right people became infected, then it really started spreading rapidly.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#229

Post by lostmsu »

mlyle wrote: post #30
pgcudahy wrote: post #6

There seems to be no analysis of whether these are neutralizing antibodies. The idea of using serology for immunity certificates or "golden tickets" is never going to go well. Even with 99.9% specificity, if the population prevalence is 1%, 10% of positives will be false positives. If in real world testing, specificity is 99% and population prevalence is 1%, then 50% of positives are false positives.

> if the population prevalence is 1% But the population prevalence is much more than 1%: 80k deaths at a 1% infection fatality rate (and I believe this is high, but I'm being conservative) implies 8,000,000 infections so far. This is more like 2.5%. So far. 95% CI for specificity is 99.5%, so you can be reasonably confident that you're doing better than 85%. It may not be a perfect intervention, but you could really…

This high prevalence is specific to a few regions though. I most states the registered total cases are still way less than 0.5%.

Re: New Abbott SARS-CoV-2 antibody test has 99.90% specificity and 100% sensitivity

#230

Post by evan_ »

aeonsky wrote: post #171
evan_ wrote: post #143

Earlier quoted context omitted.

People who have diabetes often do blood tests daily, at home, on their own, drawing a drop of blood from their finger with a lancet. If they can get it down to using a drop of blood, I think people could be convinced to test at least one member of the household daily. That should at least give us enough information to measure spread. It would be new for most people but it's not unprecedented and I think people would…

I'm sure you are aware of story behind Theranos - doing complex tests on a drop of blood is currently impossible.

I think the conclusion I would draw from the Theranos debacle is "doing hundreds of complex tests from a drop of blood is impossible", not "doing any complex test from a drop of blood is impossible."
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