Preoperative Localization and Intraoperative Parathyroid Hormone Assay in Korean Patients with Primary Hyperparathyroidism

Background: The intraoperative parathyroid hormone (IOPTH) assay is widely used in patients with primary hyperparathyroidism (PHPT). We investigated the usefulness of the IOPTH assay in Korean patients with PHPT. Methods: We retrospectively reviewed the data of 33 patients with PHPT who underwent parathyroidectomy. Neck ultrasonography (US) and 99m Tc-sestamibi scintigraphy (MIBI scan) were performed preoperatively and IOPTH assays were conducted. Results: The sensitivity of neck US and MIBI scans were 91% and 94%, respectively. A 50% decrease in parathyroid hormone (PTH) levels 10 minutes after excision of the parathyroid gland was obtained in 91% (30/33) of patients and operative success was achieved in 97% (32/33) of patients. The IOPTH assay was 91% true-positive, 3% true-negative, 0% false-positive, and 6% falsenegative. The overall accuracy of the IOPTH assay was 94%. In five cases with discordant neck US and MIBI scan results, a sufficient decrease in IOPTH levels helped the surgeon confirm the complete excision of the parathyroid gland with no additional neck exploration. Conclusion: The IOPTH assay is an accurate tool for localizing hyperfunctioning parathyroid glands and is helpful for evaluating cases with discordant neck US and MIBI scan results.