title: When initial postexcision PTH level does not fall appropriately during parathyroidectomy: what to do next?
abstract: BACKGROUND
  Inadequate fall in the intraoperative parathyroid hormone (PTH) level after removing enlarged parathyroid gland(s) typically signifies additional hyperfunctioning gland(s), prompting further neck dissection, but it may also be a false negative result. We analyzed intraoperative management of patients with an inadequate fall on PTH after excision of enlarged parathyroid gland(s).
  
  
  METHODS
  Analysis involved a prospective database of 189 patients undergoing 193 procedures for primary hyperparathyroidism. The PTH level was determined before neck incision and 10-15 min after excision of enlarged parathyroid gland(s). A PTH decrease > 50% and into normal range was used as the criterion of successful parathyroidectomy.
  
  
  RESULTS
  In 48 of 193 operations, initial postexcision PTH level did not fall appropriately. That inadequate fall in PTH level was a false negative result in 16 patients (33%) and cure was achieved without additional neck exploration in all but one patient, who had additional (negative) neck exploration after excision of a parathyroid adenoma. In all patients with false negative postexcision PTH assay, operative findings concurred with preoperative imaging tests.
  
  
  CONCLUSIONS
  Inadequate fall in intraoperative PTH may be false negative, particularly after removal of an adenoma found in the location determined by preoperative imaging. Repeat PTH may confirm the initial assay as false negative, obviating the need for additional neck dissection. Importantly, if repeat PTH does not fall appropriately, additional neck exploration needs to be performed.
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, Beth Israel Deaconess Medical Center, 330 Brookline Avenue ST919, Boston, MA 02215, USA.
authors.forename: Patrick B
authors.initials: PB
authors.lastname: O'Neal
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Poylin
authors.forename: Peter
authors.initials: P
authors.lastname: Mowschenson
authors.forename: Sareh
authors.initials: S
authors.lastname: Parangi
authors.forename: Gary
authors.initials: G
authors.lastname: Horowitz
authors.forename: Pravin
authors.initials: P
authors.lastname: Pant
authors.forename: Per-Olof
authors.initials: PO
authors.lastname: Hasselgren
mesh_terms: D000236:Adenoma / Q000097:blood / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection; D010281:Parathyroid Hormone / Q000097:blood*; D010282:Parathyroid Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000601:surgery*; D016105:Parathyroidectomy; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012086:Reoperation; D017256:Technetium Tc 99m Sestamibi; D014463:Ultrasonography
chemical_list: D010281:Parathyroid Hormone; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi