When 85 to 90% of kidney function is lost, the term "end stage kidney failure" is used and dialysis is recommended. The type of dialysis that replaces the work of the damaged kidneys by using an artificial kidney machine to filter blood is called hemodialysis. During this procedure, blood is slowly taken from the body and passed through a special filter called a dialyzer, where wastes and extra fluids are removed. The cleaned and filtered blood is then returned to the body.