The Calcium Urine test measures the amount of calcium being excreted from your body into your urine. This is a crucial diagnostic test, most often used to investigate the cause of recurrent kidney stones. High levels of calcium in the urine can be the primary reason stones form. This test, often performed on a 24-hour urine collection for the most accurate data, is also vital for assessing bone and parathyroid disorders. This test is essential for moving beyond stone treatment to stone prevention, by getting to the root of the problem.