The influence of dialysate calcium concentration on the PTH level in children undergoing CAPD.

In 12 children aged four-and-a-half to 18 years (mean 11 +/- 4.2) undergoing continuous ambulatory peritoneal dialysis (CAPD), serum intact parathyroid hormone (iPTH), ionized calcium (iCa) levels, and calcium mass transfer (CaMT) were measured on three consecutive days: day 1, after a four-hour interval between dialyses; on day 2, after four hours dwell time with peritoneal dialysis (PD) Ca 3.5 mEq/L; and on day 3, after four hours dwell time with PD Ca 2.5 mEq/L. A significantly more negative CaMT was found when PD Ca 2.5 mEq/L was used, as compared with values obtained using PD Ca 3.5 mEq/L. Significantly lower parathyroid hormone (PTH) values were found after the interval between exchanges. We conclude that in order to properly evaluate parathyroid gland function and to decide whether or not to give vitamin D metabolites, a protocol for determining PTH should be standardized.