Is it a good idea to get a covid-19 spike protein antibody test after youre fully vaccinated?

It is your choice, but not recommended necessarily. Protection could well be present even if low titers of IgG, as usual testing does not look specifically at T or B memory cells. However, you can easily purchase a study at numerous facilities.

There is not need for the test and there is no prescribed subsequent action based on the result you may get. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!