You have a few choices, including transferring your home into joint names with your sister, creating a life estate with you holding the life interest and the house passing to your sister at death, or putting it into an irrevocable trust.
Each approach has its pros and cons and each can cause a five-year waiting period for Medicaid eligibility. Another avenue, which might be the best in your situation, would be for you to execute a promissory note and mortgage to your sister. This would give your sister a right to repayment if money was left after the bank mortgage is paid off and it should not cause a five-year waiting period for Medicaid. Each of these four options has its strengths and weaknesses.
We strongly recommend that you consult with an elder law attorney, who you would have to retain anyway to put in place the strategy you choose. Find an attorney near you.