Serum Calcium Survey for Hyperparathyroidism: Results in 50,000 Clinic Patients

Fifty cases of hyperparathyroidism were found by a serum calcium survey of 50,330 individual patients in a general diagnostic clinic during a 10-year period. The diagnosis was established histologically in 44 cases and by repeated biochemical abnormalities in six patients. Many other instances of hypercalcemia are still being investigated, so that the ratio of one case of hyperparathyroidism per 1,000 individuals surveyed may be a slight underestimation. These 50 cases do not include patients referred with previously known hypercalcemia or cases found on family studies—investigation of families of patients found in this survey has allowed ascertainment of 24 additional cases of hyperparathyroidism not previously diagnosed. Detection of many apparently asymptomatic cases by calcium surveys confirms the opinion that a careful search for hyperparathyroidism must involve the screening of asymptomatic individuals for hypercalcemia. Our experience has emphasized that many of the abnormal chemical determinations found by automated procedures are easily overlooked unless individual medical units develop systems of alerting clinicians to important results.