title: Preoperative parathyroid hormone levels as a predictor of postthyroidectomy hypocalcemia.
abstract: OBJECTIVE
  The goal of the present study is to determine whether a decline in the 1-hour postoperative parathyroid hormone (PTH) level relative to the preoperative level is predictive of hypocalcemia.
  
  
  METHODS
  This is a retrospective study involving 142 consecutive patients who underwent total thyroidectomy. Changes in preoperative PTH levels were then compared with the 1-hour levels.
  
  
  RESULTS
  Thirty-four of 142 patients (23.9%) who underwent total thyroidectomy developed hypocalcemia. Thirty-one of the 34 patients who became hypocalcemic had a 1-hour postoperative PTH drop of 70% or more when compared with the preoperative value (sensitivity = 91%, specificity = 98%, positive predictive value = 94%, and negative predictive value = 97%).
  
  
  CONCLUSIONS
  A decline in the preoperative PTH level of 70% or greater at 1 hour following total thyroidectomy appears to be a reliable predictor of patients at risk of developing hypocalcemia. By allowing thyroid surgeons to identify these patients in the early postoperative period, calcium supplementation can be initiated sooner.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, McGill University, Montreal, Quebec, Canada.
authors.forename: Noah
authors.initials: N
authors.lastname: Sands
authors.forename: Jonathan
authors.initials: J
authors.lastname: Young
authors.forename: Elizabeth
authors.initials: E
authors.lastname: MacNamara
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Black
authors.forename: Michael
authors.initials: M
authors.lastname: Tamilia
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hier
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Payne
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000175:diagnosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013965:Thyroidectomy / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone