The kidney's main job is to get rid of extra fluid and waste material in your blood. Kidneys harmed by disease, injury, or birth defects lose their filtering ability. This lets dangerous levels of fluid and waste build up. This is known as kidney or renal failure (end-stage renal disease). A person with kidney failure needs dialysis or a kidney transplant to survive. Learn more about dialysis by taking this quiz. It is based on information from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).