title: Validity of early parathyroid hormone assay as a diagnostic tool for sub-total thyroidectomy related hypocalcaemia.
abstract: OBJECTIVE
  To determine the validity of early (one hour postoperatively) parathyroid hormone (PTH) assay (² 10 pg/ml), keeping gold standard as the serum ionic calcium level, for predicting sub-total thyroidectomy-related hypocalcaemia and to calculate the sensitivity and specificity of latent signs of tetany.
  
  
  METHODS
  Cross-sectional validation study.
  
  
  METHODS
  Department of General Surgery, Pakistan Institute of Medical Sciences, Islamabad from August 2008 to August 2010.
  
  
  METHODS
  Patients undergoing sub-total thyroidectomy were included by convenience sampling. PTH assay was performed 1 hour post sub-total thyroidectomy. Serum calcium levels were performed at 24 and 48 hours, 5th day and 2 weeks after surgery. Cases that developed hypocalcaemia were followed-up for a period of 6 months with monthly calcium level estimation to identify cases of permanent hypocalcaemia. Symptoms and signs of hypocalcaemia manifesting in our patients were recorded. Data was analyzed through SPSS version 10. 2 x 2 tables were used to calculate sensitivity and specificity of PTH in detecting post-thyroidectomy hypocalcaemia.
  
  
  RESULTS
  Out of a total of 110 patients included in the study, 16.36% (n=18) developed hypocalcaemia including 1.81% (n=2) cases of permanent hypoparathyroidism. The sensitivity of one hour postoperative PTH assay as a predictive tool for post-thyroidectomy related hypocalcaemia was 94.4% while its specificity was 83.6% with 53% positive predictive value and 98.7% negative predictive value.
  
  
  CONCLUSIONS
  One hour post sub-total thyroidectomy PTH assay can be helpful in predicting post sub-total thyroidectomy hypocalcaemia. Moreover, it can be useful in safe discharge of day-care thyroidectomy patients.
authors: Department of General Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad.
authors: Umbreen
authors: U
authors: Riaz
authors: Department of General Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad.
authors: Syed Aslam
authors: SA
authors: Shah
authors: Department of General Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad.
authors: Imran
authors: I
authors: Zahoor
authors: Department of General Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad.
authors: Arsalan
authors: A
authors: Riaz
authors: Department of General Surgery, Margalla Institute of Health Sciences (MIHS), Rawalpindi.
authors: Muhammad
authors: M
authors: Zubair
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002118:Calcium / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006042:Goiter / Q000601:surgery*; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D007011:Hypoparathyroidism / Q000097:blood; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D010281:Parathyroid Hormone / Q000097:blood*; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis*; D011184:Postoperative Period; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D002118:Calcium