How to Evaluate Kidney Function

Your kidneys perform three important functions. They maintain the pH fluid balance of the acidity and alkalinity. Also, they regulate your water balance and remove metabolic waste products from your bloodstream. If your have kidney problems, such as kidney disease or diabetes, toxic waste can buildup in your blood instead of being expelled in your urine. A number of laboratory testscan evaluate the cause and extent of your kidney problems.

Instructions

• 1

  Screen your urine. Your doctor can order a routine test called urinalysis when kidney problems are suspected. For instance, the test examines your urine for problems with color, appearance, bacteria or protein. The urinalysis results will give your doctor a good idea if further tests are needed.

• 2

  Assess kidney function with urine tests. Your doctor can order a variety of urine tests to evaluate your kidney function. A creatinine clearance test will show how efficiently your kidneys clear a waste product called creatinine from your blood. Creatinine is a byproduct of your muscle energy metabolism. Since it can't be recycled by your body, your kidneys must filter it out of your blood. A low clearance value in the creatinine means your there are problems with your kidneys ability to function.

  An urine osmolality test measures the number of dissolved particles in your urine. When your kidneys perform normally, they will excrete more water into the urine to dilute it. However, if your kidneys do not perform properly they start to decrease the water and your urine becomes more concentrate. Another test is an evaluation of protein in your urine. When your kidneys are healthy, they filter all proteins from your bloodstream before they reabsorbs it. A large amount of protein in your urine can indicate poor kidney function.

• 3

  Use blood tests to evaluate your kidney function. Your doctor can also use a blood sample to evaluate your kidney function. Blood Urea Nitrogen (BUN) test measures the amount of urea nitrogen in the blood. Urea, a byproduct of protein, is formed in your liver before your kidneys filter it from your blood into the urine. The more urea nitrogen in the blood means that your kidneys may not be able to adequately perform their function.

  Your doctor can also use your blood sample to measure creatinine, glucose, protein potassium and sodium in your kidneys and evaluate any problems.