Chronic kidney diseases frequently progress to end-stage renal failure over a period of several years. Ultimately, the glomerular filtration apparatus and tubulus are destroyed to such an extent that renal replacement therapy is required. This process may last longer than 10 years. To avoid loss of renal function, chronic kidney diseases should be diagnosed as early as possible so that therapeutic measures are initiated in time. Medications which prevent or delay progression to end-stage renal failure, e.g. ACE inhibitors and AT(1) blockers, are more effective if started early in the course of renal disease. A significant number of patients with chronic kidney disease are still diagnosed too late and are without adequate therapy so that chances for prevention and/or delay of chronic kidney disease are missed.