The main job of your kidneys is to remove waste and extra fluid from your body. If you have kidney disease, this waste material can build up in your blood. Over time, this may lead to serious health problems, including high blood pressure, anemia, and heart disease. This test measures creatinine levels and BUN (Blood Urea Nitrogen). Creatinine is a waste product made by your muscles as part of regular, everyday activity. Normally, your kidneys filter creatinine from your blood and send it out of the body in your urine. If there is a problem with your kidneys, creatinine can build up in the blood and less will be released in urine. If blood and/or urine creatinine levels are not normal, it can be a sign of kidney disease. The BUN test measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product that your kidneys remove from your blood. Higher than normal BUN levels may be a sign that your kidneys aren't working well. People with early kidney disease may not have any symptoms. A BUN test can help uncover kidney problems at an early stage when treatment can be more effective. You may need this test if you have symptoms of kidney disease. These include: - Fatigue - Puffiness around the eyes - Swelling in your feet and/or ankles - Decreased appetite - Frequent and painful urination - Urine that is foamy or bloody Do not eat cooked meat for 24 hours before your test.