Intraoperative parathyroid hormone levels measured by intact and whole parathyroid hormone assays in patients with Graves' disease

Purpose. To find out if the whole parathyroid hormone (wPTH) assay has practical advantages over the intact (iPTH) assay in patients with Graves' disease. Methods. We measured iPTH and wPTH levels before and after subtotal thyroidectomy in 111 consecutive patients (94 women and 17 men) with Graves' disease. Blood samples for assays were obtained after the induction of anesthesia (basal) and following skin closure (postoperative). Results. There was a significant correlation between wPTH and iPTH in both the basal and postoperative levels. Logistic regression analyses examining the relationship between the reduction in parathyroid hormone (PTH) levels and the incidence of tetany revealed that both the wPTH and iPTH assays were significantly equally predictive of postoperative tetany. Conclusion. We found that both the wPTH and iPTH assays were useful for predicting postoperative tetany in patients with Graves' disease, yielding similar results.