Chronic Kidney Disease (CKD), also known as chronic renal disease or chronic renal failure, is a progressive condition marked by the gradual loss of kidney function. The kidneys serve as a filter for the body and once damaged they can no longer remove waste and excess liquid from the blood. The kidneys are crucial for the production of blood and the regulation of blood pressure, too. The most common traditional causes of CKD are diabetes, high blood pressure and obesity. Professional guidelines classify chronic kidney disease into five stages, with stage one being the mildest and stage five the most severe. Stages one and two are classified as reversible kidney damage, while stage three and higher reflect a state of permanent damage. Without a transplant or effective dialysis, stage five is terminal.