- research personnel will also save blood and urine samples. Later, these samples will be used to test for electrolytes (salts) and proteins (that may help better predict who will get kidney problems. Subjects will not have to pay for these tests because they will not be used for usual medical care. To protect privacy, research personnel will use a code instead of name to label samples. For this reason, research personnel will not be able to tell the results of these tests.