Serum calcium testing is used to evaluate parathyroid function and blood calcium metabolism. Ionized calcium determination also helps diagnose renal failure, kidney transplantation, hyperparathyroidism, and other malignancies.

Blood calcium testing is a common procedure performed on patients with symptoms of hypocalcemia or hypercalcemia. In many cases, this test is considered part of a routine blood test, thereby helping to diagnose and detect many important medical conditions.