Because we are all* gathering for Thanksgiving, today's little knowledge dump is how Rapid Antigen Tests work.

*(In the US, unless we're not.)

Think about a virus particle. You've seen drawings, at least. There are multiple copies of the surface proteins on each particle. So multiple places for an antibody to stick.

The tube of liquid that comes in the test has anti-virus antibodies with dye molecules attached to them dissolved in it. (At low concentration, so it doesn't look colorful.) …