Endocrine Tumors

Annals of Surgical Oncology

, Volume 19, Issue 6, pp 1862-1867

Does the Final Intraoperative PTH Level Really Have to Fall into the Normal Range to Signify Cure?

  • Alexandra E. ReiherAffiliated withDivision of Endocrinology, Department of Internal Medicine, University of Wisconsin
  • , Sarah SchaeferAffiliated withDepartment of Surgery, Section of Endocrine Surgery, University of Wisconsin
  • , Herbert ChenAffiliated withDepartment of Surgery, Section of Endocrine Surgery, University of Wisconsin
  • , Rebecca S. SippelAffiliated withDepartment of Surgery, Section of Endocrine Surgery, University of Wisconsin Email author 

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Intraoperative parathyroid hormone (IOPTH) helps shorten the duration of surgery and increase the likelihood of surgical cure. Although general consensus agrees that the IOPTH should fall by 50%, there is much debate as to whether the IOPTH needs to fall into the normal range.


We retrospectively reviewed a prospective database of patients undergoing surgery for treatment of primary hyperparathyroidism. We included all patients with an IOPTH that fell by >50% by 10 or 15 min, but that did not fall into the normal range (parathyroid hormone remained ≥60 pg/ml). We excluded patients who had undergone prior neck surgery or had known multiple endocrine neoplasia 1 or 2.


A total of 1,231 patients underwent a parathyroidectomy, 155 of whom met the study’s inclusion/exclusion criteria (12.6%). A total of 117 patients had an IOPTH fall by 50% by 10 min, and 38 patients’ IOPTH fell by 50% by 15 min. Overall surgical cure rate was 98.7%. One patient from the 10-minute group and one patient from the 15-minute group had persistent disease on follow-up. One patient in the 15-minute group had recurrent disease. With a mean ± SEM 18.1 ± 2.1 months’ follow-up, the recurrence rate in this cohort was 0.6%. The average calcium at last follow-up was 9.4 ± 0.0 mg/dl.


Allowing the IOPTH to fall by 50% by 15 min, regardless of whether the IOPTH falls into the normal range, results in a high success rate when performed by experienced surgeons. This helps reduce intraoperative time used waiting for additional parathyroid hormone levels and the risks associated with unnecessary bilateral neck exploration.