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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

#171
post #143
post #126

Earlier quoted context omitted.

I believe these require a blood draw.

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.

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

#173
post #165
post #156

Earlier quoted context omitted.

That isn't true. The bats that it mostly likely come from are in China - but in Southern China about 1000 miles from Wuhan.

In Wuhan is the lab that was researching the virus from those bats.

Almost correct. The "lab" was actually doing corona virus research, and funded by the US govt.

Corona is so contagious, that combined with Wuhan being an international airport that connects to Shanghai, the #8 international airport in the world, this was the perfect storm for a pandemic.

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

#174
post #42

These stats are generated just a couple weeks after symptoms or PCR test positivity. I'm still wondering how specificity might drop off for much earlier exposures. Anecdotally: people on my Fb feed are getting positive tests they attribute to illnesses they had back in January and February. (This concern has nothing to do with the benefit these tests have in "real time" testing).

Your FB feed results don't seem impossible. First CV-19 death in CA was Feb 6 [1]. That's presumably at least a couple of weeks after infection.

[1] https://www.nytimes.com/2020/04/22/us/coronavirus-first-unit...

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

#175

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…

>>> ..they're exempt from movement and mask restrictions ... There's a negative repercussion of people around such folks getting a false-impression that masks are not a serious need (if this is in question, that's a different discussion). It also creates a possibility of visible 'haves' and 'have-nots', which can cause trouble. I think having uniform messaging for movement/masks irrespective of antibody presence will…

So the ID card goes on a lanyard.

It also creates a possibility of visible 'haves' and 'have-nots', which can cause trouble.

Yes. So? Gradually, more people are added, painfully, to the "have' list.

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

#176

I took this antibody test through LabCorp on Friday and tested positive. I have been in strict (see: paranoid) isolation with one other person since March 7 and haven't felt sick or anything close to it since then. I did have what I thought was a strange flu/cold early February with a sore throat, post-nasal drip, wildly varying body temperature, and lower back pains. In hindsight those are COVID-19 symptoms. the per…

Is a 99.9% specitivity good enough though to conclude you had covid?

Assuming you are in the US, your prior on having been infected in early February is well below 0.1% (not sure how much the covid-like symptoms would boost that). So conditionally speaking, it seems quite plausible this is a false positive.

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

#177

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…

> they can work safely Maybe. If only 1% of your employees could work safely, it's probably not worth opening the doors and paying them to try to get something done in the absence of the other 99%.

It's probably around 5% now in the Bay Area, 25% in NYC.

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

#178
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.

Would you or someone else mind expanding on this thought a little? Why does 99.9% specificity mean that 10% will be false positives? {added: great answers below} well worth understanding this point. In short specificity measures the % of the population tested which had false positives, but doesn't give you the ratio of false positives to positives or the probability that a positive test means you actually have the an…

I think it's easier to understand when you take it to the extremes: Assume nobody has the thing you're testing for. You test 100k people at 99.9% specificity, which means you get 1k positives just because of the rate. Since nobody hass the thing you're testing for, they're all false.

When the thing you're testing for is very rare, it's just as rare that the people who tested positive will actually have it.

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

#179

I took this antibody test through LabCorp on Friday and tested positive. I have been in strict (see: paranoid) isolation with one other person since March 7 and haven't felt sick or anything close to it since then. I did have what I thought was a strange flu/cold early February with a sore throat, post-nasal drip, wildly varying body temperature, and lower back pains. In hindsight those are COVID-19 symptoms. the per…

Is a 99.9% specitivity good enough though to conclude you had covid? Assuming you are in the US, your prior on having been infected in early February is well below 0.1% (not sure how much the covid-like symptoms would boost that). So conditionally speaking, it seems quite plausible this is a false positive.

> Assuming you are in the US, your prior on having been infected in early February is well below 0.1%

I think we won't know that for a while, yeah? That's part of what we could learn from these tests.

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

#180
post #156

Earlier quoted context omitted.

I believe DNA studies have linked the origin to bats in the area of wuhan

That isn't true. The bats that it mostly likely come from are in China - but in Southern China about 1000 miles from Wuhan.

What species? What is their range? Do they migrate?
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