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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

#91

Post by Dylan16807 »

InvaderFizz wrote: post #49
gwd wrote: post #23

Earlier quoted context omitted.

Let me give it a try. Suppose we have 100,000 people in a statistically representative town. If 1% of people have had COVID-19, then that's 1000 people who have had it, and 99,000 people who haven't. The test has a sensitivity of 100%, which means all 1000 people who've had it will test positive. The test has a specificity of 99.9%, which means 98,901 of the 99,000 people who haven't had it will test negative; but th…

So if I'm understanding this correctly, with this test. If you test negative, you are clear, guaranteed, no false negatives. If you test positive, there is a 10% chance it's a false positive. I guess my follow up question, does a retest of the positive population make that false positive rate drop to 0.1%, or is the reason for false positive significant to an individual and not random chance?

> If you test positive, there is a __% chance it's a false positive.

This percentage is based on both the test and the real infection rate.

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

#92

Post by thoraway1010 »

guscost wrote: post #40
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…

Just took the Quest version today. I traveled a lot in February but only felt mildly under-the-weather once, so it's a long shot. Even if I was exposed, we don't really know the seroconversion rates for mild/asymptomatic cases.

My test results didn't share what platform was used.

- August

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

#93

Post by jfoster »

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…

I have been wondering why it is considered to have originated in Wuhan rather than Wuhan simply being the first major outbreak where it was identified as a novel coronavirus. Is it always the case that hospitals will be capable of identifying a new type of virus based on some patients who look like they have the flu?

One thing that's known about covid-19 is that it has an unusual spread pattern. In some circumstances it might not spread too much (eg. average R0 is well less than 10) but in other circumstances where air is recirculating a lot or a particular patient is very contagious, it seems to spread a lot more. Couple that with many people being asymptomatic. So, what if it had been spreading in many places but Wuhan was simply the first place where it was detected? It seems to be capable of spreading without being detected for quite a while in many other parts of the world. (eg. Singapore's foreign worker dormitories)

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

#94

Post by xyhopguy »

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…

people say that because .25% of the population in NYC are dead from covid. we dont see those numbers here -- if it was widespread in feb, what caused the discrepancy?

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

#95

Post by timr »

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…

MERS and SARS are not a huge concern (they never achieved wide circulation), but coronaviruses make up ~40% of what we know as the common cold.

That said, if the false positive rate were that high, the specificity of the test would be low.

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

#96

Post by fourstar »

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…

Would you mind describing that lower back pain a little bit more? Location, sensitivity, etc?

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

#97

Post by chrischen »

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…

I had post nasal drip and runny nose and my Forward doctor ruled it out as Covid based on that.

This was after having cold symptoms in Dec last year already (usually I would only get sick once a year).

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

#98

Post by indecisive_user »

rconti wrote: post #78
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…

Interesting. I've long been of the opinion that I was definitely NOT exposed to it, although I had a persistent lingering cold in late feb/early march. (Symptoms took way longer than usual to clear -- but no flu symptoms). That said, if it was in California before folks thought it was, it's theoretically possible. My wife works in a hospital and will be tested for COVID-19 and antibodies, FINALLY, sometime this week…

This is your wife whom you presumably spend most of your time with and sleep next to, right?

With the long incubation period and how contagious it is, I'd assume the chance of a false negative (.1% in the new Abbott test) would be higher than her having caught it and somehow not passing it to you.

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

#99

Post by samatman »

ghshephard wrote: post #47
barbegal wrote: post #22

> We tested 1,020 serum specimens collected prior to SARS-CoV-2 circulation in the United States and found one false positive This gives 95% confidence intervals of between 0.0% and 0.5% false positive rate.

Okay - I'm going to reveal my statistics ignorance here - but if they did get a false positive, how does 0.0% fall within the range of possibilities (or is that allowing for it might be 0.0499..% or lower?)

All of the sibling answers are correct, but ignoring another possibility: that the timeline is simply wrong, and SARS2 was present in the US early enough that the "false positive" is in fact a true positive.

Which can't lead to a "true 0%", since there's no such animal. But it could mean that all of the tests gave correct answers, in the trial.

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

#100

Post by Scipio_Afri »

timr wrote: post #95
thoraway1010 wrote: post #89

Earlier quoted context omitted.

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…

MERS and SARS are not a huge concern (they never achieved wide circulation), but coronaviruses make up ~40% of what we know as the common cold. That said, if the false positive rate were that high, the specificity of the test would be low.

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.
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