Three primary ways to test for kidney disease are a blood pressure measurement, urine test, and blood test.
A test for high blood pressure is important because it can cause kidney disease. However, it is doubly important because high blood pressure can indicate a kidney problem.
The urine test is simple: you give a sample, which will be tested for protein, a waste product called creatinine, and red and white blood cells. Too much protein or too little creatinine may indicate that your kidney isn't filtering your blood properly.
A blood test can show how well your kidneys are functioning by testing how much of the waste product creatinine is present in your bloodstream; an above-normal measurement may indicate reduced kidney function. Blood can also be tested for urea, a protein waste product that should be filtered out of the blood by the kidneys.
If these three routine screenings indicate that your kidneys aren't functioning properly, your doctor may suggest tests such as ultrasounds, CT scans, and MRIs that can take pictures of your kidneys. He may also do a kidney biopsy, where a sample is taken through a needle to be analyzed for kidney disease.