Recently, cats are being more frequently identified with an elevated level of calcium in their blood for which no cause is found after routine testing. This is called “idiopathic hypercalcemia”, and can lead to urinary bladder stones and possible kidney failure. It is speculated that this condition may be the result of increased bone resorption in these cats, leading to decreased bone density. This study will evaluate bone density and bone metabolism of cats with idiopathic hypercalcemia as compared to healthy control cats using dual energy x-ray absorptiometry (DEXA) scanning and various blood and urine tests. The results of this study may help guide future treatment for this condition.