Microalbumin-Creatinine-Ratio is a urine albumin test. If your kidney has any kind of damage or any kidney disease, then this test is performed to measure the amount of albumin present in your urine. Albumin is basically a protein which your body uses for the growth of the cells and helps repair its tissues. This protein is generally present in your blood and a certain amount of it in your urine is a sign that you may have a kidney disease. The function of the kidney is to filter out all the wastes and let the nutrients and proteins such as albumin in your blood. A damaged kidney will let albumin spill into your urine.