duh. I wonder what that test is actually good for. The big test draws multiple vials , they need to be quickly centrifuged in the vac vials preloaded with varying secret sauces ... and the plasma is tested for several Immunoglobulins (IgA, IgG, IgM) The appearance and quantity of these varies based on timeline ( how their curves peak) from infection and how severe the virus got in you. \ In Each of those Immunoglobulins they look at/for four antigens present: spike glycoprotein 1 (s1) receptor binding domain spike glycoprotein 2 (s2), and nucleoprotein