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Testing for Antibodies in Covid-19 Patients

There are many types of antibody tests available, each using one of 3 different methods.  They can measure 2 different types of antibodies:  Immunoglobulin M (IgM), which usually appears first, and /or Immunoglobulin G (IgG) which usually doesn't appear until after 2 weeks.  The Infectious Disease Society of America expert panel currently recommends testing sometime between the 3rd and 4th week after symptoms develop in patients in which this information is important.  It is most helpful in symptomatic patients whose SARS-CoV-2 virus test is negative. 

But these antibody tests are not routinely recommended for an individual patient, because the presence of antibodies doesn't mean that they are immune and may give a false sense of security.  These serologic tests are most useful when screening large populations of people in order to assess the prevalence of past infections by region. Continue Reading


I live in New York City and results of 1.5 million antibody tests were recently released from the Dept of Health.  Antibody tests for Covid-19 were positive in more than 27% of NYC residents, and the numbers varied by zip codes, and boroughs.  In one zipcode more than 50% of the antibody  tests were positive, demonstrating a high incidence of Covid-19 at some time during the Spring or Summer. 


Thank you for the explanation. My granddaughter in law consistently test negative for Covid even though she had the same symptoms and works at a place where seven people tested positive. Now after two weeks she’s feeling sick again. She doesn’t want to get tested for Covid again because she’s already had four tests. My thought was to get an antibody test and I will now share what you’ve shared with my daughter. Maybe no one will want to give her one but it may be the only way she finds out that she actually had it.

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