Use

This quantitative test, performed with a 24‑hour urine specimen, may help screen for hypercalciuria, one of the established risk factors for kidney stone formation. It also helps assess metabolic disorders of calcium metabolism such as hyperparathyroidism, bone disease, and idiopathic hypercalciuria. In general, 24‑hour urine specimens are preferred to random urine specimens when measuring calcium for diagnostic evaluation of hypercalciuria. Calcium is essential for bone formation and nerve, muscle, and heart functions. Calcium metabolism is regulated by parathyroid hormone and vitamin D metabolites. Urinary calcium excretion reflects kidney tubular filtration and reabsorption as well as dietary intake, intestinal absorption, and bone resorption. Creatinine excretion is useful in determining whether the 24‑hour urine specimen has been fully and accurately collected, as daily urinary creatinine excretion shows minimal fluctuation.