http://kidney.niddk.nih.gov/kudiseases/pubs/kidneytests/
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
Healthy kidneys remove wastes and excess fluid from the blood. Blood tests show whether the kidneys are failing to remove wastes. Urine tests can show how quickly body wastes are being removed and whether the kidneys are leaking abnormal amounts of protein.