title: A single parathyroid hormone level obtained 4 hours after total thyroidectomy predicts the need for postoperative calcium supplementation.
abstract: BACKGROUND
  Parathyroid hormone (PTH) levels after total thyroidectomy have been shown to predict the development of symptomatic hypocalcemia and the need for calcium supplementation. This study aimed to determine whether a PTH level drawn 4 hours postoperatively is as effective as a level drawn on postoperative day 1 (POD1) in predicting this need.
  
  
  METHODS
  This is a single-institution retrospective review of 4-hour and POD1 PTH levels in patients who underwent total thyroidectomy from January 2012 to September 2012. If POD1 PTH was ≥10 pg/mL, patients did not routinely receive supplementation; if PTH was <10 pg/mL, patients received oral calcium with or without calcitriol.
  
  
  RESULTS
  Of 77 patients, 20 (26%) had a 4-hour PTH <10 pg/mL; 18 (90%) of these patients had a POD1 PTH <10 pg/mL. No patient with a 4-hour PTH ≥10 pg/mL had a POD1 PTH <10 pg/mL. All 18 patients with POD1 PTH <10 pg/mL received calcium supplementation. Three additional patients received supplementation due to reported symptoms or surgeon preference. A 4-hour PTH ≥10 pg/mL compared with a POD1 PTH had a similar ability to predict which patients would not need calcium supplementation; sensitivity was 98% vs 98%, specificity was 90% vs 86%, and and negative predictive value was 95% vs 95%. Of 21 patients who received supplementation, 13 (62%) also received calcitriol, including 9 patients (69%) with a 4-hour PTH <6 pg/mL.
  
  
  CONCLUSIONS
  A single PTH level obtained 4 hours after total thyroidectomy that is ≥10 pg/mL accurately identifies patients who do not need calcium supplementation or additional monitoring of serum calcium levels. Same-day discharge, if deemed safe, can be accomplished with or without calcium supplementation based on the 4-hour PTH level. Greater consideration should be given to calcitriol supplementation in patients with a 4-hour PTH <6 pg/mL.
authors: Department of Surgery, Medical College of Wisconsin, Milwaukee, WI.
authors: Azadeh A
authors: AA
authors: Carr
authors: Department of Surgery, Medical College of Wisconsin, Milwaukee, WI.
authors: Tina W
authors: TW
authors: Yen
authors: Department of Medicine, Medical College of Wisconsin, Milwaukee, WI.
authors: Gilbert G
authors: GG
authors: Fareau
authors: Department of Surgical Oncology, MD Anderson Cancer Center, Houston, TX.
authors: Ashley K
authors: AK
authors: Cayo
authors: Department of Surgery, Medical College of Wisconsin, Milwaukee, WI.
authors: Sarah M
authors: SM
authors: Misustin
authors: Department of Surgery, Medical College of Wisconsin, Milwaukee, WI.
authors: Douglas B
authors: DB
authors: Evans
authors: Department of Surgery, Medical College of Wisconsin, Milwaukee, WI. Electronic address: tswang@mcw.edu.
authors: Tracy S
authors: TS
authors: Wang
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002117:Calcitriol / Q000008:administration & dosage*; D002118:Calcium / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011183:Postoperative Complications; D011184:Postoperative Period; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000601:surgery; D013965:Thyroidectomy / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D002117:Calcitriol; D002118:Calcium