Kidney function tests determine how effectively the kidneys are removing extra fluid and wastes from the blood, explains the National Kidney Foundation. Urine tests determine the swiftness of waste removal and if the kidneys are allowing anomalous amounts of protein to leak through.
Three different types of blood tests measure kidney function, notes the National Kidney Foundation. A blood urea nitrogen test measures the urea nitrogen broken down from proteins in food. Normal levels range from 7 to 20, and the higher the number, the less work the kidney is doing. Another blood test is the glomerular filtration rate. This measures the effectiveness of the removal of wastes and fluids from the blood. Normal values are at least 90. The serum creatinine test should come back with a 1.2 maximum for women and a 1.4 maximum for men. If creatinine, a waste product, rises in the blood, the kidneys are not doing their job properly.
With urinalysis, a chemically treated strip is used to test for anomalies such as excess pus, blood, protein, sugar and bacteria in the blood, as excess amounts of these substances cause the strip to change colors, according to the National Kidney Foundation. Microalbuminuria tests look for a protein called albumin inside the urine, which can indicate kidney malfunction. Creatinine clearance tests are used to compare the creatinine in a sample of urine to a blood test to show the blood filtered out by the kidneys.