CPT Code(s)

82340

Methodology

Spectrophotometry (SP)

Limitations

Oral contraceptive use may depress results. Requires accurate 24-hour urine collection.

Reference Range(s)

Unrestricted Calcium Diet

Clinical Significance

Urinary calcium reflects dietary intake, rate of calcium absorption by the intestine and bone resorption. Urinary calcium is used primarily to evaluate parathyroid function and the effects of vitamin D. A significant number of patients with primary hyperparathyroidism will have elevated urinary calcium. However, there are other clinical entities that may be associated with increased urine calcium: Sarcoidosis, Paget's disease of bone, vitamin D intoxication, hyperthyroidism and glucocorticoid excess. Decreased urine calcium is seen with thiazide diuretics, vitamin D deficiency and familial hypocalciuric hypercalcemia.