Renal Dialysis is primarily used to provide an artificial replacement for lost kidney function (renal replacement therapy) due to renal failure. Dialysis may be used for very sick patients who have suddenly but temporarily, lost their kidney function (acute renal failure) or for quite stable patients who have permanently lost their kidney function (stage 5 chronic kidney disease). For patients with stage 5, or End-Stage Kidney Disease (ESKD), the treatment that most naturally replaces lost kidney function is a kidney transplant. However, some patients are not good candidates for a transplant due to medical or other reasons, some cannot receive a transplant because of the short supply of donor kidneys, and others simply decide that a transplant is not the best option for them. As a result, most patients with ESKD must rely on dialysis to replace the water and waste removal functions of the healthy kidneys.