In the context of acute or chronic kidney failure, renal function may diminish to a point at which it is no longer able to adequately support life. When this happens, renal replacement therapy is indicated. Renal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD).