title: Biochemical diagnosis of primary hyperparathyroidism: Analysis of the sensitivity of total and ionized calcium in combination with PTH.
abstract: OBJECTIVE
  To investigate the accuracy of the biochemical diagnosis of primary hyperparathyroidism (pHPT) in a consecutive series of patients with operatively verified disease.
  
  
  METHODS
  Four hundred thirty-six patients with pHPT, 340 women and 96 men, were reviewed. Biochemical variables, including total calcium (Ca), ionized calcium (Cai) and PTH were analyzed and registered in a prospective database.
  
  
  RESULTS
  In the subgroup of patients with more mild hypercalcemia (Ca below 2.70mmol/L) the correlation between Ca and Cai was poor. 19 respectively 18 patients had preoperatively a Ca respectively Cai level within the reference range. Further 35 patients had preoperatively a normal level of PTH. The diagnostic sensitivities, in detecting pHPT, for Ca, Cai and the combination of Ca and Cai were 96%, 96% and 99%.
  
  
  CONCLUSIONS
  If calcium and ionized calcium are not used in the diagnostic workup of pHPT some 4% of the patients will be overlooked. We recommend analyzing both Ca and Cai in the diagnostic workup of pHPT.
authors.affiliation: Department of Surgery, Lund University Hospital, Lund, Sweden. kristinanordenstrom@hotmail.com
authors.forename: E
authors.initials: E
authors.lastname: Nordenström
authors.forename: P
authors.initials: P
authors.lastname: Katzman
authors.forename: A
authors.initials: A
authors.lastname: Bergenfelz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002118:Calcium / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D007477:Ions; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011300:Preoperative Care; D012016:Reference Values; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D007477:Ions; D010281:Parathyroid Hormone; D002118:Calcium