The following items are examined in the urine examination: urine red blood cells, urine white blood cells, urine protein, urine specific gravity, urine volume, and color. An increase in bilirubin in urine often indicates liver problems, because bilirubin is mainly metabolized in the liver after the destruction of red blood cells. Positive urine protein often represents kidney disease, especially when nephrotic syndrome is present. Positive red blood cells in urine are often seen in glomerulonephritis, or when there is an increase in glomerular filtration rate due to other causes.