Laboratory Evaluation of Renal Disease Blood Tests Blood Urea Nitrogen (BUN) Plasma Creatinine (Cr) Urine Tests Urinalysis ‘Dip Stick’ Sediment Renal Blood Tests (BUN, Cr) The function of the glomerulus is plasma filtration Thus, one measure of renal function is the glomerular filtration rate or GFR Assessment of Glomerular Filtration Creatinine is a product of muscle creatine metabolism Creatinine is released into the blood at a constant rate Assessment of Glomerular Filtration Creatinine is not protein bound and is filtered at the glomerulus Thus it is a useful measure of blood clearance Glomerular Filtration Rate (As measured by Creatinine Clearance) Urine Flow (ml/d) x Ucr (mg/dL) CrCl....