Patient Preparation

In stone evaluation, urinary calcium results are more meaningful if the patient initially is on his/her usual diet for three days prior to urine collection. Drugs affecting mineral metabolism include antacids, phos-phates, glucocorticoids, carbonic anhydrase inhibitors, anticonvulsants, and diuretics including thiazides. Thiazides are used therapeutically to lower urine calcium excretion. If the patient is on a stone prevention regime and test is for follow-up, then medications should not be stopped for the test.