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Potential false-positive rate among the 'asymptomatic infected individuals'

ncbi.nlm.nih.gov

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Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#11

Post by gus_massa »

nck4222 wrote: post #2

Interesting, as this means that China would be quarantining more people than "necessary", which would help slow the pandemic anyway. I can't imagine an asymptomatic person would put stress on the hospital system? But maybe I'm wrong there. I am curious if this also could indicate a false-positive problem with non asymptomatic people as well. False-positives are also why the CDC tests had to be shipped back, although…

> I can't imagine an asymptomatic person would put stress on the hospital system?

If s/he is in the hospital in quarantine you must give blankets and food, probably a nurse to check the temperature and symptoms two or three times per day, a medical doctor one a day just to be sure. Perhaps a blood analysis from time to time?

Luckily you don't have to handle visitors because they are in quarantine. (Or there are some visits? What if one patient tries to escape?) You must give an official reports for the family. Now you can assume the patient can send a WhatsApp message to the family saying s/he is fine, but you need probably still an official report. Paperwork, there is also paperwork.

How isolated are them from each other. If they are all together, you can transform the overcrowded false positives in real patients.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#12

Post by mempko »

lbj wrote: post #9

In Denmark we increased our testing 10-fold and found 300% more people infected. Our response to that increase has been to shut down the country completely for 2 weeks and expand our governments right to act: Forced entry into private property, forced isolation and treatment, forced testing. If this is all because of an error in the test kit I'm going to be super ticked off.

Or think about it this way, this means as a percentage of real people infected, the mortality rate of COVID-19 is higher than thought. This false-positive rate means that the number of real cases is lower than reported and therefore mortality rate is higher. In other words, COVID-19 is more dangerous than thought if you catch it. Then again, I'm sure the actual cases dwarfs those reported since not everyone has been tested.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#13

Post by taborj »

mempko wrote: post #10

Wait, so the actual mortality rate for COVID-19 is much higher than thought because of all the false positives on cases without symptoms?

But that also means that it doesn't spread as quickly/easily as originally thought. Right?

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#14

Post by glofish »

mempko wrote: post #12
lbj wrote: post #9

In Denmark we increased our testing 10-fold and found 300% more people infected. Our response to that increase has been to shut down the country completely for 2 weeks and expand our governments right to act: Forced entry into private property, forced isolation and treatment, forced testing. If this is all because of an error in the test kit I'm going to be super ticked off.

Or think about it this way, this means as a percentage of real people infected, the mortality rate of COVID-19 is higher than thought. This false-positive rate means that the number of real cases is lower than reported and therefore mortality rate is higher. In other words, COVID-19 is more dangerous than thought if you catch it. Then again, I'm sure the actual cases dwarfs those reported since not everyone has been…

Mortality is almost always much lower than the initially reported and observed numbers.

There could be many more people that never even get to the testing phase.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#15

Post by Scarblac »

bluGill wrote: post #7
nck4222 wrote: post #2

Interesting, as this means that China would be quarantining more people than "necessary", which would help slow the pandemic anyway. I can't imagine an asymptomatic person would put stress on the hospital system? But maybe I'm wrong there. I am curious if this also could indicate a false-positive problem with non asymptomatic people as well. False-positives are also why the CDC tests had to be shipped back, although…

I'm starting to hear stories that the Chinese people demanded more quarantine than was needed. The problem got bad enough that the government decided to comply as it wouldn't hurt much more than the amount of quarantine was needed and might even help.

I really wonder how we're going to look back at this in a few years.

On the one hand, no matter what measures politics takes here (the Netherlands), every political party is clamouring for more. That suggests to me that we'll probably end up doing too much.

On the other hand, the scenes from Hubei and Italy are horrific, we're going to get them here as well, it could be far worse, we absolutely must act now.

On the third and fourth hands, the total number of deaths so far wouldn't even make a serious flu season in a single country, and fatality rates are all over the place depending on the country.

Very confusing. Still, better too much than too little.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#16

Post by jmartinpetersen »

lbj wrote: post #9

In Denmark we increased our testing 10-fold and found 300% more people infected. Our response to that increase has been to shut down the country completely for 2 weeks and expand our governments right to act: Forced entry into private property, forced isolation and treatment, forced testing. If this is all because of an error in the test kit I'm going to be super ticked off.

This is somewhat misleading information.

First, the country has NOT been completely shut down. I went shopping today and bought milk, yeast and flour. We didn't need toilet paper, but the store had plenty. All schools and most of the public sector closes down for two weeks on Monday. Some business (like restaurants, movie theaters and fitness gyms) are closing down on their own accord. But you can - if you will - still go shopping for clothes, gardening stuff, electronics and most importantly food.

Second, although the right to forced entry into private property was in the original draft it was removed before vote. Entry still follows the known rules of needing approval by a judge.

You are right, however, that forced testing, forced treatment, forced vaccination (if/when possible) and forced quarantine is mandated as per discretion of the public health authorities.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#17

Post by glofish »

mempko wrote: post #10

Wait, so the actual mortality rate for COVID-19 is much higher than thought because of all the false positives on cases without symptoms?

it all depends what "higher than thought" means.

If you mean the day-to-day numbers, those will always show variations, and paradoxically those will even show a substantial uptick once the spread slows down.

The most vulnerable are affected first and most severely.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#18

Post by cultus »

One fallacy that seems universal with healthcare folks is they think the false positive rate is the chance that a given positive result is erroneous. If an illness is rare, a positive result in a test with a 1% error rate might have an overwhelming probability of being a false positive. This is why prior probabilities need to be taken into account in making decisions.

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#19

Post by ses1984 »

cultus wrote: post #18

One fallacy that seems universal with healthcare folks is they think the false positive rate is the chance that a given positive result is erroneous. If an illness is rare, a positive result in a test with a 1% error rate might have an overwhelming probability of being a false positive. This is why prior probabilities need to be taken into account in making decisions.

>If an illness is rare, a positive result in a test with a 1% error rate might have an overwhelming probability of being a false positive.

Can you elaborate on this a little more...?

Re: Potential false-positive rate among the 'asymptomatic infected individuals'

#20

Post by nn35 »

How did they estimate this? If anybody can read the actual paper, I’d love to know.

If false positives dominate true positives then you’d expect total positives to depend primarily on number of tests given, right? Which sounds wrong to me, but I’d be interested in hearing other thoughts.

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