Intraoperative PTH monitoring during parathyroidectomy: the need for stricter criteria to detect multiglandular disease

Purpose. Usefulness of rapid intraoperative parathyroid hormone assay (RI-PTH) for diagnosis of multiglandular disease during parathyroidectomy is still debated. Materials and methods. Two hundred seven patients were selected for focused parathyroidectomy for a suspicious single adenoma. RI-PTH results were interpreted on the basis of our criteria for prediction of multiglandular disease (a < 50% drop from the highest pre-excision level and/or a T20 concentration higher than reference range and/or >7.5 ng/L higher than the T10). The results of these criteria were compared with the Miami Criterion (MC). Results. One hundred ninety-seven uniglandular disease and ten multiglandular disease were found. Our criteria identified all but one patient with multiglandular disease (false positive (FP) rate 0.5%; specificity 90%). On the basis of MC, RI-PTH monitoring would have resulted in five FP results, with a specificity of 50%. Conclusions. Despite the higher rate of unnecessary bilateral exploration, our criteria results in a lower FP, markedly reducing the risk of missing multiglandular disease.