The urinary system's ability to filter the blood resides in about 2 to 3 million tufts of specialized capillaries known as the The glomeruli filter the blood based mostly on particle size, large elements like blood cells, platelets, antibodies, and are excluded. is determined mostly by the breakdown products of Cells are not normally found in the urine. The presence of (urine analysis) often provides clues to renal disease. The color of urine destruction, which creates a yellow pigment known as may indicate a urinary tract infection. are byproducts of fat metabolism. Finding ketones in the urine suggests that the body is using fat as an energy source in preference to glucose: this may be a sign of diabetes mellitus