PTH and Hypercalcemia: Normal ionized Ca. Creatinine < 160 μmol/L and either a) serum Ca < 2.50 mmol/L + PTH > 55 ng/L or b) serum Ca 2.50 to 2.60 mmol/L + PTH ≥ 35 ng/L. Checked for persistence (≥ 3 occasions). Excluded malabsorption and family history of hypercalcemia