I got Hep B shots through work because I am trained in CPR and advanced first aid. they do I think 2 shots then do blood titers to see if it worked. they did 2 shots, titer, no work, 2 more shots, titer, did not work. A year later when they had nurse on site they did 2 shots, then titer and I was good. Every single multiple failure from the visiting nurses was a success with on site nurse, we are talking like 30 people.
They CAN do titers for MMR but they are more expensive than just getting the 2 shot MMR again.
They take blood to do titers for Hep B.