Symptomatic hyperparathyroidism Asymptomatic hyperparathyroidism with any of the following: 24-hour urinary calcium > 400 mg (see Foot Note, below) serum calcium > 1 mg/dL above upper limit of normal Creatinine clearance > 30% below normal for patient's age Bone density > 2.5 standard deviations for below peak (i.e., T-score of -2.5) People age < 50