Alore EA, et al. - In the Veterans Affairs (VA) health care system, researchers examined how primary hyperparathyroidism is diagnosed in patients with hypercalcemia and the use of parathyroidectomy for the treatment of primary hyperparathyroidism. This national cohort study included 371,370 veterans with chronic hypercalcemia. Serum parathyroid hormone level was measured to evaluate primary hyperparathyroidism in 86,887 (23.4%). Hormonal evidence of primary hyperparathyroidism was reported for 47,158 patients of which 6,049 (12.8%) underwent definitive treatment with parathyroidectomy. These findings suggest underdiagnosis of primary hyperparathyroidism even with the presence of chronic hypercalcemia, and its undertreatment with parathyroidectomy regardless of surgical indications.