Diagnosis of Renal Failure is confirmed by blood tests measuring the buildup of waste products in the blood. BUN, creatinine, and GFR are routine blood tests used to measure the buildup of waste products in the blood. BUN and creatinine become elevated, and the glomerular filtration rate (GFR) decreases. This is the rate with which blood is filtered through the kidneys and can be calculated based upon the creatinine level, age, race, and gender. Urine tests may be done to measure the amount of protein, detect the presence of abnormal cells, or measure the concentration of electrolytes. Protein in the urine is not normal and can be a clue that damage to the kidneys has occurred. Abnormal aggregations of red and white blood cells called ...