Used to investigate disorders of calcium metabolism and absorption, bone resorption and renal loss; evaluates bone disease, calcium renal stones (nephrolithiasis), hypercalciuria, and follow-up of patients on calcium therapy for osteopenia. Urine calcium output is dependent on dietary calcium and will be reduced on a low calcium diet. Testing assumes an average calcium diet of 800 mg/d.

Collect urine in a 24-hour urine container with no preservative.