Could there be a difference between the tdap test and the TB test?

TDAP VaccinePPD test. Tdap ia vaccine to prevent Diptheria,Tetanus andPertussis And PPD is a skin test for Tuberculosis.
Test vs not a test. The TB skin test is actually a test.A small amount of the test material in injected into the superficial layer of skin and 48-72 hours later will be judged for the amount of reaction (thickening & or redness) that is triggered as the body reacts to the test.The tdap is a vaccine (not a test) that is injected into the muscle & triggers production of antibodies.