Examination of the urine plays a vital role in the diagnosis of kidney diseases. Proteinuria is an important indicator of renal disease and the types of proteins found in the urine help distinguish glomerular and tubular disorders. The findings of casts and blood cells in the urine provide valuable clues about the causes of the underlying renal pathology. Crystals may be found in the urine of healthy individuals and in patients with urolithiasis, toxic damage, and chronic renal failure.