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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

#251

Post by iso947 »

gridlockd wrote: post #19
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.

What if prevalence is 5% or 10%? Your alarming false positive rates vanish. No measure is ever going to work perfectly.

At an individual basis it can still be problematic as you can still get a super spreader who thinks they are immune, picks it up, then spreads it.

On a population basis it’s more helpful.

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

#252

Post by IanCal »

apatters wrote: post #234
bb2018 wrote: post #227

Earlier quoted context omitted.

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 th…

What specific evidence would you be expecting to see in December or January? The infection fatality rate for this disease is probably below 1%, and we don't know what percentage of the population is infected. We don't truly know how quickly it spreads. Nursing home populations are at greater risk, but even if the IFR is 3-5% for that cohort, the population mortality would be some fraction of that, and most of the dea…

> Nursing home populations are at greater risk, but even if the IFR is 3-5% for that cohort, the population mortality would be some fraction of that,

Looking much higher than that. 80+ is 15-20% and 70-79 is 8% (https://www.worldometers.info/coronavirus/coronavirus-age-se...). It'll be concentrated more in people with pre-existing conditions so I expect nursing homes would see greater figures than that.

> Statistics from Kirkland now appear to tell the national story. Of 129 staff members, visitors and residents who got sick, all but one of the 22 who died were older residents,

https://www.theguardian.com/us-news/2020/may/11/nursing-home...

So we're not talking about one or two deaths but a large proportion of your residents suddenly getting ill in the same way and of those a large proportion dying over a short period.

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

#253

Post by blackrock »

Nice! Last year, in July 2019, in Virginia, there were a bunch of strange flu like illnesses, leading to pneumonia, and deaths [1]. When will these people get tested for the antibodies?

[1] https://abcnews.go.com/US/respiratory-outbreak-investigated-...

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

#254

Post by rswail »

timr wrote: post #115
Scipio_Afri wrote: post #100

Earlier quoted context omitted.

These tests are not FDA approved, they're being allowed under emergency use authorization. They're not subject to the same rigger as tests normally allowed on the market and the manufacturer's specifications may be overstated.

"They're not subject to the same rigger as tests normally allowed on the market and the manufacturer's specifications may be overstated." "rigor" Also, the error bars on these may be wider than is usual for an approved test, but they are just as likely to be understated as overstated.

"rigour" :)

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

#255

Post by JoshuaDavid »

kevin_thibedeau wrote: post #111
ardit33 wrote: post #101

I took this test this Friday (Quest Direct) in NYC and tested negative. In late Feb. I had a 'flu like symptoms' with fever and massive headache for few days. What worried me later is that I had the 'can't taste anything' symptom a week later. No coughing though. If you read online, you see people swear they had it at some point this winter. So, if you had a 'flu like' symptoms in Feb or early March, perhaps it was j…

If the government was serious about homeland security and restoring the economy they would be subsidizing testing full boat.

I don't know that fully subsidizing testing would necessarily be enough to satisfy demand for testing, but at $100 per test x 300M Americans x call it 1 test per week, you're looking at $30B per week to test everyone every week, if testing really can scale up that far. Which is (extremely) expensive but still less than the current stimulus packages and economic damage.

I actually kinda wonder whether the ROI is high enough that it makes sense for some of the bigger investment funds to subsidize these tests. There are $4T under passive management in the US, so it would cost less than 1% of that number to test every American once at current market prices. If doing so would boost the market by at least 1%, it seems like it would have positive ROI to do so (and I for one would be happy if the index funds I'm invested in did so).

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

#256

Post by s1t5 »

vikramkr wrote: post #167
s1t5 wrote: post #64

Earlier quoted context omitted.

Specificity and sensitivity feel really poorly chosen and difficult to remember. You could swap their definitions and the names of the terms would make just as much sense. I much prefer true positive rate and true negative rate.

Those named could be confusing to. True positive rate = .95 could be interpreted as, if you get a positive result, that's a 5% chance of a false positive, when the percent chance of the test being a false positive given a positive result is actually a function of the true positive percentage in the population and not innate to the test.

That kind of confusion has nothing to do with the terms though, it just requires a deeper understanding of the process and the statistics around it.

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

#257

Post by m463 »

ikeyany wrote: post #135
kevin_thibedeau wrote: post #111

Earlier quoted context omitted.

If the government was serious about homeland security and restoring the economy they would be subsidizing testing full boat.

The government has made it clear that this is about politics and business, not safety or public health.

When NYC said it would give free meals to anyone with no id check or possibility of being turned down to be refreshing and a solution without politics or hidden agendas.

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

#258

Post by Ladyady »

DoingIsLearning wrote: post #249
Ladyady wrote: post #244

If you live in the UK, you can get Abbott's test from Forth: https://www.southwalesargus.co.uk/news/18441478.first-to-mar...

> All kits can be purchased online with the samples taken in the home or workplace, before being sent away for analysis. Is this possible for other EU countries or is the lab analysis/transport limited to UK only?

On Forth's FAQ it says: "Our service is available within the UK only, if you live outside this territory you will not be able to buy this test."

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

#259

Post by e_y_ »

thoraway1010 wrote: post #89
cerebral_oasis wrote: post #38

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…

The results I got had a big FDA warning that positive results may be a result of other infections (ie, that the tests are not specific to covid). I feel like the WHO (body may not produce antibodies as part of beating covid, antibodies have not been shown to confer any immunity) and now the FDA may be talking about true but theoretical issues. What is the REAL rate, in the USA, of folks who have for example MERS anti…

Although I think the WHO has been way too cryptic talking about the issues surrounding antibodies and immunity, I think the real questions are really around degrees of immunity.

It might be that 80% of people get antibodies and immunity, but 20% don't. Or some people get antibodies but it doesn't prevent them from being a carrier. Or the immunity is only partial, etc. And then there's the ADE stuff which is theoretical but scary.

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

#260

Post by np_tedious »

y-c-o-m-b wrote: post #75
jrockway wrote: post #68

Earlier quoted context omitted.

Good anecdote. I also had a "weird cold" in February with symptoms that are unusual for me but typical of COVID-19, and have been waiting to get the antibody test. I kind of expect it to turn out the same way. (Otherwise, I would really like to figure out what the "weird cold" that everyone had in February was. Because it sure was weird, and everyone I know had it.)

"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…

This is just about identical to my experience in early March. No (or at least no observed) fever, a distinctive but not awful sore throat, and intense fatigue. Urgent care clinic did not test for the virus, or even for the flu.

I tested positive for antibodies last week.

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