FDA just cleared a $20 Covid-19 antibody test • Hacker News Board

Re: FDA just cleared a $20 Covid-19 antibody test

#171

Post by yokaze » Sat, Mar 21, 2020, 4:10 AM UTC

hedora wrote: post #132

teruakohatu wrote: post #73

Earlier quoted context omitted.

Slightly off topic question: do people who have been infected with those varieties have any sort of immunity against covid-19?

Some health professional floated the theory that kids aren’t getting it as much as the rest of the population because they’ve recently been hammered with all the coronaviruses at daycare. I’m hoping this is true, since it suggests new parents are mostly OK too.

The theory I've heard: Children mostly rely on their innate immune system compared to adults, where the adaptive immune system is more fully developed. In elderly people, the immune response of both systems is slower/weaker.

Re: FDA just cleared a $20 Covid-19 antibody test

#172

Post by jariel » Sat, Mar 21, 2020, 9:48 AM UTC

chki wrote: post #67

jariel wrote: post #35

They need to be free, universal, and possibly mandated in some areas. Given the 'cost' is shutting down the economy and 1 trillion Fed bailout, it's probably worth widespread distribution of these things, and nailing down 'everyone' who has it, just as S. Korea is doing. They have not 'shut down' their country, they're just aggressive at going after cases.

This test will not be able to help by shipping it out to everyone. As someone else in this thread already described, if you give everybody in the US this test, the probability that if someone tests positive he/she is not actually infected is well over 99%. Also there will be a lot of cases where people are infected but haven't had an antibody reaction yet. Those will not test positive.

The test will still be immensely helpful.

Most people who are infected don't know it, this will tag mamy of them.

The 'false positives' can be taken care of by a visit to the hospital.

The 'no antibodies yet' can be taken care of by self-isolation - within a few days, they'll have antibodies and can test again.

Re: FDA just cleared a $20 Covid-19 antibody test

#173

Post by Maxion » Sat, Mar 21, 2020, 11:19 AM UTC

kragen wrote: post #37

jupp0r wrote: post #24

> The sensitivity is 97.90 %, the specificity is 91.77%. This seems like it could provide a false sense of security to many if used widely by the general population.

It also means that, if that number is correct, 8.23% of not-yet-infected people will test positive. At a time when only 0.01% of people are infected, that means that 8.2301% of people will test positive, and of those people, on average one person† of every 82301 people will have the infection; the other 82300 are all false positives. They'll need to improve that for this to be useful, since at the time 1% of the popu…

I'm a little confused at your calculations.

With a population size of 1000 and with 0.01% of the population infected (i.e. 1 individual) with this test we'd get 82 false positives and 0.979 true positives.

For every true positive result in your population, you'll have 8 false positive results and 0,021 false negatives.

Re: FDA just cleared a $20 Covid-19 antibody test

#174

Post by Maxion » Sat, Mar 21, 2020, 11:33 AM UTC

socksy wrote: post #126

jupp0r wrote: post #82

Earlier quoted context omitted.

I feel like false positives are less damaging than false negatives at this point. Unnecessarily putting people into self quarantine is not the worst, as opposed to giving false security to potentially infectious people.

Not so great if people are using to test to see if they're "immune"

Testing should perhaps not be done at home, at all.

True positives could be sent for PCR testing to confirm whether they are infected or already cleared.

Negatives that show symptoms could likewise be sent for PCR testing.

This way, you'd massively reduce the strain on PCR testing resources.

Re: FDA just cleared a $20 Covid-19 antibody test

#175

Post by pas » Sat, Mar 21, 2020, 12:12 PM UTC

joe_the_user wrote: post #123

absherwin wrote: post #45

This is an antibody test which will only be positive days after the onset of symptoms. This is principally useful for several purposes: 1. Figuring out who to isolate in hospitals if the RNA test isn't available in sufficient quantity 2. Understanding who has already recovered from COVID-19 and is thus immune with all that implies in terms of inability to spread the disease and reduced need for PPE 3. Enabling us to…

This is an antibody test which will only be positive days after the onset of symptoms. This isn't really what your Twitter link says. That links says: "Both IgM & IgG (those are two different kinds of antibodies, with IgA being a third) were low or undetectable at day 0, but increased by day 5 in nearly all patients (N=16)" -- Reports strongly indicate there are many infected people who are asymptomatic after five da…

Is this test able to detect that someone is infected before they start to infect others?

Re: FDA just cleared a $20 Covid-19 antibody test

#176

Post by DanBC » Sat, Mar 21, 2020, 12:13 PM UTC

pas wrote: post #175

joe_the_user wrote: post #123

Earlier quoted context omitted.

This is an antibody test which will only be positive days after the onset of symptoms. This isn't really what your Twitter link says. That links says: "Both IgM & IgG (those are two different kinds of antibodies, with IgA being a third) were low or undetectable at day 0, but increased by day 5 in nearly all patients (N=16)" -- Reports strongly indicate there are many infected people who are asymptomatic after five da…

Is this test able to detect that someone is infected before they start to infect others?

No. This test tells us that you had covid-19 in the past and recovered from it.

Re: FDA just cleared a $20 Covid-19 antibody test

#177

Post by joezydeco » Sat, Mar 21, 2020, 3:27 PM UTC

amvalo wrote: post #169

joezydeco wrote: post #166

Earlier quoted context omitted.

I’ve used some of their other home testing kits before, like their colon cancer screening kit. Detects globin at 50 ng/mL and is board approved by gastroenterologists. The company isn’t a scam.

Yeah, after digging into it more I saw that. Doesn't explain the missing FDA number though which is quite sketchy.

Their number is listed in the info brochure.

https://cdn.shopify.com/s/files/1/1010/0544/files/COVID19Bro...

Re: FDA just cleared a $20 Covid-19 antibody test

#178

Post by product50 » Sat, Mar 21, 2020, 7:36 PM UTC

joshmaker wrote: post #51

product50 wrote: post #32

Earlier quoted context omitted.

Some smart ass always has to comment how this is not perfect and thus not useful. Look at the alternatives. Should we just keep on waiting otherwise?

But there are other tests, the US just didn't use them. South Korea has had tremendous success with testing. > On Feb. 4, two weeks after South Korea reported its first coronavirus case, the government gave “emergency approval” for Seoul-based Kogene Biotech to move ahead with the test kits. > Kogene currently exports test kits for the novel virus to 35 countries in Asia, Europe and the Middle East. https://www.washi…

Not true. Go deeper. There was ~10% false negatives in South Korea too. But it is still much better than nothing. But of course no on here will say anything about it since everything America does is likely bad and foreign countries are always a step ahead.

Re: FDA just cleared a $20 Covid-19 antibody test

#179

Post by kragen » Sat, Mar 21, 2020, 7:44 PM UTC

Maxion wrote: post #173

kragen wrote: post #37

Earlier quoted context omitted.

It also means that, if that number is correct, 8.23% of not-yet-infected people will test positive. At a time when only 0.01% of people are infected, that means that 8.2301% of people will test positive, and of those people, on average one person† of every 82301 people will have the infection; the other 82300 are all false positives. They'll need to improve that for this to be useful, since at the time 1% of the popu…

I'm a little confused at your calculations. With a population size of 1000 and with 0.01% of the population infected (i.e. 1 individual) with this test we'd get 82 false positives and 0.979 true positives. For every true positive result in your population, you'll have 8 false positive results and 0,021 false negatives.

0.01% of 1000 is 0.1 people, not 1 people, and 82÷1 is 82 and not 8, but you're right that my calculations weren't correct either. You'd get 82 false positives and 0.1 (or 0.0979) true positives, so for every true positive result, you have 820 false positives, not 82300 as I said.

Re: FDA just cleared a $20 Covid-19 antibody test

#180

Post by chki » Sat, Mar 21, 2020, 9:15 PM UTC

jariel wrote: post #172

chki wrote: post #67

Earlier quoted context omitted.

This test will not be able to help by shipping it out to everyone. As someone else in this thread already described, if you give everybody in the US this test, the probability that if someone tests positive he/she is not actually infected is well over 99%. Also there will be a lot of cases where people are infected but haven't had an antibody reaction yet. Those will not test positive.

The test will still be immensely helpful. Most people who are infected don't know it, this will tag mamy of them. The 'false positives' can be taken care of by a visit to the hospital. The 'no antibodies yet' can be taken care of by self-isolation - within a few days, they'll have antibodies and can test again.

>The 'false positives' can be taken care of by a visit to the hospital.

That would overwhelm hospitals immediately.

>The 'no antibodies yet' can be taken care of by self-isolation - within a few days, they'll have antibodies and can test again.

But if the test is negative you don't know that you should self-isolate. That would mean everybody needs to self-isolate but then we don't need the test.