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Antibody test for Covid?

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  1. #41

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    Quote Originally Posted by HK_Katherine:
    Yes, I ordered the kit linked in my original post, (cost HKD480 for 2 tests) it finally arrived after about 3 weeks and we tested both myself and hubby. Both negative. And yes, I know the tests are dodgy with a low accuracy rate, but given his severe illness was in January, and we know how little virus is circulating in HK from the ongoing lack of community transmission, it just served to confirm the reasonably high probability of it just being flu.
    thanks, I was offered one for free. Was just curious on the price range for the rest of friends and family. I will give it a try. I'll need to find out if my three weeks of feeling shit in February were combined hangovers or the flu.
    HK_Katherine likes this.

  2. #42

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    Quote Originally Posted by HK_Katherine:
    Yes, I ordered the kit linked in my original post, (cost HKD480 for 2 tests) it finally arrived after about 3 weeks and we tested both myself and hubby. Both negative. And yes, I know the tests are dodgy with a low accuracy rate, but given his severe illness was in January, and we know how little virus is circulating in HK from the ongoing lack of community transmission, it just served to confirm the reasonably high probability of it just being flu.
    Congratulations, your husband isn't pregnant. But that is about all the tests tell you. (Wondfo makes pregnancy tests)

    After British complaints about the test kits surfaced, both Chinese companies blamed British officials and politicians for misunderstanding or exaggerating the utility of the tests. Wondfo told Global Times, a Chinese newspaper, that its product was intended only as a supplement for patients who had already tested positive for the virus.
    https://www.nytimes.com/2020/04/16/w...y-test-uk.html

    Last month, the Spanish government withdrew 58,000 Chinese-made coronavirus testing kits from use after it emerged that they had an accurate detection rate of just 30 per cent
    Could have spent $480 on alcohol and flipped a coin, would have given you a more accurate result.

    https://www.telegraph.co.uk/news/202...ntibody-tests/

  3. #43

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    Maybe CT scans or spirometry tests are more reassuring?


  4. #44

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    I had read those newspaper articles about the UK tests being dodgy before I even ordered this kit, and checked the company marketing it and the underlying manufactuer and confirmed its likely the same test.

    As noted in my post above "I know its not accurate".

    But I think to say that it's just a pregnancy test or "no better than a coin flip" is silly. Even a 70% accurate test is better than a coin flip and these are better than that. The UK government have been saying they will use them for "population analysis" - ie to get a general feel of total numbers positive rather than specfics, which I don't think they would do on a 70% accuracy only. Attached the insert from the box so you can see what they say about their own test.

  5. #45

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    Quote Originally Posted by mrgoodkat:
    Congratulations, your husband isn't pregnant. But that is about all the tests tell you. (Wondfo makes pregnancy tests)



    https://www.nytimes.com/2020/04/16/w...y-test-uk.html



    Could have spent $480 on alcohol and flipped a coin, would have given you a more accurate result.

    https://www.telegraph.co.uk/news/202...ntibody-tests/
    Actually a 30% accuracy rate is pretty good, what you don't want is a 50% rate since then it's the equivalent of coin flipping. The risk here will be the false negatives. I'll try the one I got since it's free. But not having high hopes.

  6. #46

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    Quote Originally Posted by Plutark:
    Actually a 30% accuracy rate is pretty good, what you don't want is a 50% rate since then it's the equivalent of coin flipping. The risk here will be the false negatives. I'll try the one I got since it's free. But not having high hopes.
    Normally, to get FDA approval, diagnostic makers need to run trials to gather evidence on their tests’ performance, a process that can take months or even years. The agency is currently skipping a lot of those steps by issuing emergency use authorizations.

    Manufacturers are now required to run their Covid-19 tests on a minimum of 30 positive samples and 30 negative samples. They must demonstrate to the agency that the test has at least a 95 percent sensitivity, meaning it must correctly identify at least 95 percent of the positive samples as having the coronavirus, and 100 percent specificity, meaning that it must accurately identify all the negative samples as not having the coronavirus.
    30% accuracy is pretty shit. Wondfo is also not approved by the FDA, probably because they don't reach the required accuracy.

    Edit: That's the only approved "home test". You still need to send the sample back though. https://www.pixel.labcorp.com/at-hom.../covid-19-test

  7. #47

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    Quote Originally Posted by mrgoodkat:
    30% accuracy is pretty shit. Wondfo is also not approved by the FDA, probably because they don't reach the required accuracy.

    Edit: That's the only approved "home test". You still need to send the sample back though. https://www.pixel.labcorp.com/at-hom.../covid-19-test
    No, I'm talking statistics. When faced with a Yes/No question, 30% accuracy means the opposite too. If the test is wrong 70% of the time, then if I flip the answer it is right 70% of the time. It doesn't matter where your ROC curve is as long as it not in the middle, a curve between 70-80 is good:


    The only important thing is what is the tolerance for False positive and False negative. For example in cancer testing you do not want to have false negative. Better a false positive to then be tested again to make sure.

    For Covid-19 you don't want that either but not to the same extent. Anyway, let's wait until they come with proper test, right now it's like the far west where everyone is trying to get the first in the shelves.

  8. #48

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    Quote Originally Posted by mrgoodkat:
    30% accuracy is pretty shit. Wondfo is also not approved by the FDA, probably because they don't reach the required accuracy.

    Edit: That's the only approved "home test". You still need to send the sample back though. https://www.pixel.labcorp.com/at-hom.../covid-19-test
    That's not an antibody test

  9. #49

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    Dear, items as such come with false positives and false negatives. If these really work, who would medical professionals test the risk of doing throat swab which can stimulate coughing and hence their risk of being infected?

    More importantly, there is a broad time frame between infection to antibody being produced by the body. I don't see any value in this kit.


  10. #50

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    Quote Originally Posted by Victoriastar:
    Dear, items as such come with false positives and false negatives. If these really work, who would medical professionals test the risk of doing throat swab which can stimulate coughing and hence their risk of being infected?

    More importantly, there is a broad time frame between infection to antibody being produced by the body. I don't see any value in this kit.
    Antibody tests are useful if you are looking for antibodies. Unfortunately some people try and use them to identify positive covid, which is not what they are useful for. I was looking for antibodies.

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