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 99mTc-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% false-negative. 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.