Clinical impact of two different intraoperative parathyroid hormone assays in primary and renal hyperparathyroidism

Intraoperative parathyroid hormone (PTH) monitoring predicts successful surgery for primary hyperparathyroidism (pHPT). In renal HPT, intraoperative PTH assays can define whether parathyroid resection is adequate.

Intraoperative PTH was measured with two different immunometric assays (Immulite Turbo DPC and ADVIA Centaur assay) in 91 patients undergoing parathyroidectomy for primary (n=57) and renal (n=34) hyperparathyroidism. PTH was monitored preoperatively, 10, 20, and 30 min after parathyroidectomy and 24 h postoperatively.

Ten minutes after parathyroidectomy, intraoperative PTH dropped into the normal range (<7.6 pmol/l) in 84% of patients with pHPT and tertiary HPT as measured with the ADVIA Centaur assay (PTH-A), compared with 100% of the samples measured with the Immulite Turbo DPC assay (PTH-I; P=0.0082). Twenty minutes after parathyroidectomy for secondary HPT, intraoperative PTH decreased to the normal range in 100% measured with PTH-I compared with 50% measured with PTH-A (P=0.009). Then, 24 h postoperatively, PTH-I and PTH-A levels were within the normal range in all of the successfully treated patients. Both assays correctly identified six patients with persistent disease and another patient with a double adenoma in pHPT.

In patients undergoing parathyroidectomy for primary or renal HPT, PTH levels decreasing to the normal range indicated successful surgery in all of the patients as measured with the PTH-I assay. Comparing the two assays, PTH-I was able to quantify the intraoperative PTH decay more quickly than PTH-A.