Laboratory diagnosis of primary hyperparathyroidism.

Although considerable effort has gone into the development and modernization of indirect parathyroid function tests, recent experience indicates that they do not possess adequate diagnostic specificity or sensitivity to provide a definitive diagnosis of HPT when they are most needed, that is, in mild or intermittent hypercalcemia. Conversely, in most research and some commercial laboratories, the combination of hypercalcemia and an elevated mid-molecule or intact PTH level will be diagnostic in more than 90% of patients.