The urine albumin-creatinine ratio (uACR) shows whether you have albumin in your urine. Albumin is a type of protein that's normally found in the blood.Your body needs protein. It's an important nutrient that helps build muscle, repair tissue, and fight infection. But it should be in your blood, not your urine. When you have albumin (protein) in your urine, it is called albuminuria or proteinuria.One of the main jobs of your kidneys is to filter your blood. Your kidneys keep important things your body needs inside your blood, like protein. They also remove things your body doesn't need, like wastes and extra water.