Kristian G. AndersenGeverifieerd account

I have seen a lot of similar tweets and discussions. Please note that these are *not* diagnostic tests - they are serology tests, which measure antibodies, not the virus. 1/nhttps://twitter.com/vaitor/status/1241337295606657033 …

Serology tests are great to measure people who have been exposed previously, but they typically cannot be used to accurately diagnose acute patients - that requires detecting the pathogen itself (in this case HCoV-19), and not the antibodies (IgM or IgG) produced against it. 2/n

Antibodies only come up much later in infection and typically too late to be useful for diagnosis. E.g., IgM likely takes 10+ days after infection to develop, while IgG takes longer still (likely at least 14+ days). 3/n

Typically when we talk about "rapid diagnostic tests" (RDTs) those tests detect the antigen derived from the pathogen, not the antibodies against it. RDTs are typically blood-based tests and can often be done doing a simple fingerstick. 4/n

The main issue trying to do this to diagnose COVID-19, is the fact that the virus typically can't be found in the blood, so these blood-based tests won't work for diagnosis. 5/n