Chasing the Drop: Miami Versus Dual Criteria for Intraoperative Parathyroid Hormone Monitoring in Primary Hyperparathyroidism.

Aim To compare the diagnostic performance of the Miami criterion and the Dual criterion for intraoperative parathyroid hormone (IOPTH) monitoring in patients undergoing parathyroidectomy for primary hyperparathyroidism, and to assess factors contributing to operative failure. Methodology A single-center retrospective observational study was conducted involving 23 consecutive patients who underwent parathyroidectomy with IOPTH monitoring between January 2023 and June 2025. The Miami criterion (≥50% parathyroid hormone (PTH) reduction from baseline at 10 minutes) and the Dual criterion (≥50% reduction with final PTH in the normal range) were applied. Operative success, defined as normocalcemia at three months, served as the gold standard. Diagnostic performance was assessed by sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. Results At three months, 19 of 23 patients (82.6%) achieved normocalcemia. The Miami criterion demonstrated higher sensitivity (89.5%) and accuracy (78.3%) compared with the Dual criterion (78.9% and 69.6%, respectively). Both criteria showed high PPV (85.0% vs. 83.3%). Four operative failures (17.4%) were attributed to parathyroid carcinoma with metastases, non-localizing or ectopic adenomas, and vitamin D deficiency. Conclusions Both Miami and Dual IOPTH criteria reliably predicted postoperative normocalcemia, with the Miami criterion demonstrating higher sensitivity and accuracy. Operative failures were related to disease complexity rather than biochemical criteria. Advanced localization strategies and metabolic optimization should be integrated into perioperative planning to improve outcomes.