[Test with calcitonin as an index of parathyroid function in chronic renal failure]

The aim of this study was to evaluate the clinical usefulness of the calcitonin test in predicting the hyperparathyroid bone disease severity in uremia. 200 IU of synthetic salmon calcitonin was given intranasally to 77 hemodialysed patients with end-stage renal failure. Before the test, serum calcium, PTH and serum alkaline phosphatase had been sampled; serum calcium was determined also in 2 to 4 hours after. The subjects were divided into 3 groups according to their serum PTH levels. Group I consisted of 24 patients with at least 10-fold serum PTH elevation, group II of 34 patients with intermediate values, and group III of 19 patients with serum PTH within normal range. In the group I the mean serum calcium fall was 0.32 +/- 0.16 mmol/l (1.28 +/- 0.64 mg/dl) (p < 0.001) and 0.27 +/- 0.15 mmol/l (1.08 +/- 0.60 mg/dl) (p < 0.001), after 2 to 4 hours respectively. In the group II serum calcium decreased by 0.16 +/- 0.12 mmol/l (0.64 +/- 0.48 mg/dl) after 2 hours and by 0.14 +/- 0.09 mmol/l (0.56 +/- 0.36 mg/dl) after 4 hours; the differences were statistically insignificant. In the group III no reduction in serum calcium was observed. In the whole 77 patients population significant linear correlations between the hypocalcemic response and iPTH as well as serum alkaline phosphatase were found. Our results confirm that the calcitonin-induced hypocalcemia a test can be, in addition to serum alkaline phosphatase and PTH evaluation, a simple and useful index of advanced hyperparathyroid bone disease in hemodialysed patients with chronic renal failure.