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How long after infection will an antibody test work? I have had 2 instances of suspected Covid infection, one where my friend who I had met outside for a walk a

• nradov 5y ago
  There's no simple answer. It really depends on severity of symptoms, length of the disease course, and immune system response. Some patients never produce detectible levels of antibodies, in others they may persist for years. Patients who receive a negative antibody test after a suspected COVID-19 case might want to get a T cell test since that is another way to confirm previous infection. https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-adaptive-biotechnologies-t-detect-covid-test https://www.fda.gov/news-events/press-announcements/coronavi...
• crazygringo 5y ago
  Almost certainly yes. The half-life of antibody levels has been estimated at 73 days. Good, commonly available antibody tests are quite sensitive, and they're accurate besides (99%), and time has not been enough of a factor yet to produce false negatives for this reason. In a year or two it might be. As far as I'm aware, there's currently no evidence of people having "weak" antibody responses such that tests don't pick it up in a way that they fall below 99% accuracy. The only time concern is that you need to wait 2-3 weeks until after you recover from COVID to ensure you test positive, as they take time to build up.