A microalbumin-to-creatinine ratio test is used to diagnose and monitor kidney disease in at-risk people, according to Mayo Clinic. The test measures the amount of albumin, or protein, in a patient's urine. That amount is compared to the creatinine, or waste product, also found in the urine.
The microalbumin-to-creatinine ratio test gives doctors an accurate view of how well the kidneys are functioning. The body excretes creatinine steadily. Comparing the amount of albumin with the amount of creatinine in the same specimen lets doctors know if the kidneys are getting rid of the albumin as steadily. If the results of this test are high, it may indicate kidney disease, according to Mayo Clinic.