https://www.cdc.gov/coronavirus/2019-ncov/testing/serology-overview.html

THERE'S A SPIKE!!! YES DUMMY BECAUSE WE HAVE INCREASED TESTING EXPONENTIALLY!!!

So according to the CDC the common cold can give you a positive antibody test. We've been saying it but here's the CDC to confirm it.

"A positive test result shows you might have antibodies from an infection with the virus that causes COVID-19. However, there is a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the Common Cold."