How do the antibody tests available, for example from Labcorp and others, relate to these findings? They won't give a peptide readout, but they do have both spike protein and nucleocapsid tests. I'm trying to determine if there's a test worth taking to tell me if I previously caught the virus or if I have some level of pre-existing antibody response.

I imagine the nucleocapsid test (164068) https://files.labcorp.com/labcorp-d8/202.... would return positive if you've in fact caught the bug, or you have 4 or more of the 5 matches (80% of the population is cross reactive). Or, is that not quite right?

I'm not sure why the spike protein antibody tests are being marketed other than that's the infection mechanism everyone has been talking about for the last year, and that's what your immune system would target after the vaccines. So, the market is there, but from a natural infection/immunity perspective it seems like the wrong test.