4 ms·

Literally false positive and false negatives. In other words, if you test millions of people, there will be more people tested positive who DON'T have the disea

Literally false positive and false negatives. In other words, if you test millions of people, there will be more people tested positive who DON'T have the disease vs. those who test positive and HAVE the disease.

stubish 7y ago
If you know the false positive and false negative rates, then you can predict how many in a sample size of millions will end up falsely identified in this way. What I don't know and what the article doesn't seem to mention is if the false positive rates are known yet and if we have more or less than the expected number of 'reinfected'.
- eanzenberg 7y ago
  Nothing about Covid19 testing is statistical right now. Why? Because tests are scarce and are used by medical professionals to save lives. There will be time for rigorous statistical analysis after this epidemic is under control.
devy 7y ago
Exactly! For any medical tests, there are 2 measurements: sensitivity and specificity, one to judge false positive and another judge the false negatives. https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity
- AzzieElbab 7y ago
  Spain sent testkits back to China because they were unreliable
  - tehjoker 7y ago
    In the NYT article on Italy today, frontline medics were saying that clinical symptoms were anecdotally more reliable than the tests because there are too many false negatives. Not sure whose tests they're using but I've heard similar things about US PCR tests. https://www.nytimes.com/interactive/2020/03/27/world/europe/coronavirus-italy-bergamo.html?action=click&module=Spotlight&pgtype=Homepage https://www.nytimes.com/interactive/2020/03/27/world/europe/...
    - devy 7y ago
      Yep! CT scans and clinician's experience is more reliable than any tests for COVID-19 diagnostics (which should only serving as a definitive confirmation). This also why I believe human doctors are still unbeatable by AI
      - perl4ever 7y ago
        I think that's missing the point, which is that the only way to get the necessary accuracy is to use multiple independent sources of information. It's not whether clinicians are better than tests or vice versa, but that no single datum is good enough.
        devy 7y ago
        No. The point is, COVID-19 testing kit is in extreme short supply everywhere in the world right now given most countries are locked down and the viral outbreak patients are growing at an exponential rate, the next reliable way to diagnose COVID-19 for clinicians without testing kits is to use CT (which gets results fast and inexpensive and the equipment is universally accessible in every hospital) scans and find some patterns, which is exactly what doctors in Wuhan did during the early phase of the outbreak[1]. [1]: https://www.ncbi.nlm.nih.gov/pubmed/32134681 https://www.ncbi.nlm.nih.gov/pubmed/32134681
        perl4ever 7y ago
        Well, that's your point, but I think everyone knows the tests are scarce.
      - davnn 7y ago
        > This also why I believe human doctors are still unbeatable by AI. Because you hypothesize that they can rapidly learn new, not very distinctive patterns without much data?
        devy 7y ago
deleted 7y ago
[deleted]

stubish 7y ago

If you know the false positive and false negative rates, then you can predict how many in a sample size of millions will end up falsely identified in this way. What I don't know and what the article doesn't seem to mention is if the false positive rates are known yet and if we have more or less than the expected number of 'reinfected'.

eanzenberg 7y ago
Nothing about Covid19 testing is statistical right now. Why? Because tests are scarce and are used by medical professionals to save lives. There will be time for rigorous statistical analysis after this epidemic is under control.

devy 7y ago

Exactly! For any medical tests, there are 2 measurements: sensitivity and specificity, one to judge false positive and another judge the false negatives. https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity

AzzieElbab 7y ago
Spain sent testkits back to China because they were unreliable
- tehjoker 7y ago
  In the NYT article on Italy today, frontline medics were saying that clinical symptoms were anecdotally more reliable than the tests because there are too many false negatives. Not sure whose tests they're using but I've heard similar things about US PCR tests. https://www.nytimes.com/interactive/2020/03/27/world/europe/coronavirus-italy-bergamo.html?action=click&module=Spotlight&pgtype=Homepage https://www.nytimes.com/interactive/2020/03/27/world/europe/...
  - devy 7y ago
    Yep! CT scans and clinician's experience is more reliable than any tests for COVID-19 diagnostics (which should only serving as a definitive confirmation). This also why I believe human doctors are still unbeatable by AI
    - perl4ever 7y ago
      I think that's missing the point, which is that the only way to get the necessary accuracy is to use multiple independent sources of information. It's not whether clinicians are better than tests or vice versa, but that no single datum is good enough.
      - devy 7y ago
        No. The point is, COVID-19 testing kit is in extreme short supply everywhere in the world right now given most countries are locked down and the viral outbreak patients are growing at an exponential rate, the next reliable way to diagnose COVID-19 for clinicians without testing kits is to use CT (which gets results fast and inexpensive and the equipment is universally accessible in every hospital) scans and find some patterns, which is exactly what doctors in Wuhan did during the early phase of the outbreak[1]. [1]: https://www.ncbi.nlm.nih.gov/pubmed/32134681 https://www.ncbi.nlm.nih.gov/pubmed/32134681
        perl4ever 7y ago
        Well, that's your point, but I think everyone knows the tests are scarce.
    - davnn 7y ago
      > This also why I believe human doctors are still unbeatable by AI. Because you hypothesize that they can rapidly learn new, not very distinctive patterns without much data?
      - devy 7y ago

deleted 7y ago

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