There are many causes of kidney disease.  Urine studies can give us a clue to see if the damage is coming from the glomerulus, which is the filter in the kidney.  There are about a million glomeruli in each kidney.  These glomeruli filter the blood, and the filtrate that is produced is then processed, with the main function being to get rid of waste products in the blood.  Normally, protein and blood cells are held back and do not enter the urinary space.  So, if we see blood cells or protein in the urine, then this is usually reflective of damage to the filters.  There are many causes which could lead to this damage and determining the cause by the nephrologist can help prevent continued damage to the kidney.