Antibody Testing

Wouldn't you love to know that you are immune to COVID-19?  For me and my colleagues this would be very valuable information. It wouldn't make me careless in my approach to taking care of patients, but it would take a lot of the fear and anxiety out of it.  I would be more apt to volunteer to work in our respiratory clinic to help spare other providers who are not immune.  I asked my partner how it would change his life.  He quickly responded that if he knew that he and his family were immune, his kids would be allowed to throw their arms around Grandma and Grandpa and give them a big hug.  Our public service workers could do their jobs easier, more safe and with less restrictions if we knew for sure that they were immune. 

The easy response is, "well let's get the antibody test done on everyone."  It sure sounds good on the surface but it is not as cut and dry as it may seem. Here are some points to consider:

1. Quality of the tests: The FDA has loosened the usual quality assessment requirements for labs to develop the test.  Those control measures have not yet all been validated. They are starting to be done now, but we are not yet sure who has the most accurate results.  

2. False negative tests: No one is advocating using this test as a means to diagnose active infection with the SARS CoV2 virus. Antibodies are developed by our immune system to fight future infections but the process takes 3-6 weeks to occur.  If blood is drawn within that time, the test may be negative but the infection may be present.  For example, if I see a patient who was stuck by a bloody needle at the hospital, I will order antibody tests for hepatitis and HIV. The reason to do so is to document whether or not that patient already has those diseases to begin with.  I will then order another test in six weeks to see if that exposure resulted in infection. Therefore, a negative test has three possible interpretations. It can indicate a new infection, an inadequate immune response or someone who has never been exposed to the virus in question. 

3. False positive tests: This is the more concerning of the scenarios.  If some has a positive test and feels that they are immune but are not, they may put themselves in higher risk situations.  In our current situation, there is concern that there could be cross reactivity to the other corona viruses that have been in the community for many years but cause mild disease.  More studies need to be done to determine the specificity of the new tests for our current strain. Until those studies are done, it does not do much good to perform the test. 

4. Experimental application. The one scenario that is currently being studied where the test will be useful is in individuals who were known to have COVID-19 and have recovered. If they have a positive antibody test, their serum might be used as a treatment for others with severe disease.  Studies are ongoing at Washington University. If anyone would like to participate, here is the contact information:

Email: IDCRU@wustl.edu or call 314-454-0058.

As much as we would all love to know our immune status to this virus, it is best to wait till more information is available. In the meantime, I protect you be being careful, just as you protect me. We are in this together.