What are the factors that determine Medicaid eligibility, and whether a procedure or service is covered?

I believe it depends on the state. I live in Wisconsin and am on 'Badger Care', Wisconsin's Medicaid. I was eligible because of my income and being a divorced mother of 2 who's father doesn't work and won't cover them. They go by a set income standard. If you are below the income limit, then you are eligible. You are also eligible if you or the other parent can't provide coverage.