The calcium infusion test in primary hyperparathyroidism.

Abstract

Abstract The calcium infusion test as described by Kyle et al. (10), which involves measurement of forenoon phosphate clearance before and after a calcium infusion, has been performed in 10 patients with primary hyperparathyroidism (PHP), 4 with non‐parathyroid hypercalcemia and in 12 control patients together with 11 patients with other diseases (kidney stone, peptic dyspepsia, and normocalcemic sarcoidosis). The fall in phosphate clearance (F%) indicated the degree to which the parathyroid glands could be suppressed. F% did not completely differentiate patients with PHP from normocalcemic patients because of a marked overlap. Only values less than 10% were indicative of PHP. In patients with non‐parathyroid hypercalcemia a low F% was also found and was dependent upon the degree of hypercalcemia. In normocalcemic patients F% was found to be dependent upon the increase in serum calcium concentration which could be achieved during infusion. This correlation was not found in patients with PHP. No relationship was found between the degree of adenoma activity, expressed by the serum calcium concentration, and F%. Whether forenoon phosphate clearance was suited as a criterion for differential diagnosis of PHP was also studied. This did not appear to be the case.