Diabetic nephropathy is one of the major late complications of diabetes and is associated with substantial cardiovascular morbidity and mortality and is a leading cause of end stage renal disease (ESRD) in the Western world. In clinical practice, renal impairment is diagnosed by albuminuria or proteinuria and/or changes in serum creatinine/creatinine clearance indicating alterations of the glomerular filtration rate (GFR). However, the inter-individual variability is high, and as a consequence, these standard tests have a moderate specificity and sensitivity at early stages of disease, with major limitations in the diagnosis of the early stages of diabetic nephropathy (DN).