Until recently, it was thought that kidney disease was comparatively rare. Now, however, a new blood test, the eGFR, has revealed that it may affect up to four per cent of the adult population. The real prevalence may be higher as it is often undiagnosed, especially when part of a condition such as diabetes which itself suffers from lack of diagnosis. Kidney disease may also be associated with high blood pressure and heart disease.The kidneys are a pair of bean-shaped organs that lie on either side of your spine in the lower middle of your back whose main function is to remove waste products and excess water, processing about 200 litres of blood a day. Symptoms of disease are many and various, ranging from weakness and loss of appetite, to frequent urination, swelling and easy bruising, altered mental state, and high blood pressure.Treatment focuses on slowing the progression of the disease and treating any underlying condition and may include controlling blood sugar in diabetes; control of high blood pressure; dietary measures; and dialysis. The topics include: understanding the kidneys; the failing kidney; tests and investigations; treatment; the vital importance of self-help - tips on lifestyle, diet and fluid intake; and, surgery, dialysis and transplant.