Hemodialysis is the process of purifying the blood of a person whose kidneys are not working normally. Hemodialysis functions are similar to an artificial kidney in patients with kidney failure and other renal impairments. Hemodialysis uses the artificial membrane to remove waste, such as urea, from the blood, restore the proper balance of electrolytes in the blood, and eliminate extra fluid from the body. Hemodialysis can be done in a hospital, in a dialysis center that is not part of a hospital, or at home.