An advanced diagnostic evaluation is usually required to determine whether there is abnormal activity in the parathyroid glands and to identify the cause of the elevated calcium, in order to tailor a treatment plan for each individual. Modern hormonal tests, ultrasound imaging, nuclear scintigraphy, and metabolic evaluation can help establish early diagnosis and provide rational guidance for therapeutic decisions. The sooner a hyperparathyroidism diagnosis is made, the better the chance of preventing complications that compromise bones, kidneys and cardiovascular function.