Biochemical diagnosis of primary hyperparathyroidism: Analysis of the sensitivity of total and ionized calcium in combination with PTH

Clin Biochem. 2011 Jul;44(10-11):849-52. doi: 10.1016/j.clinbiochem.2011.04.002. Epub 2011 Apr 15.


Objectives: To investigate the accuracy of the biochemical diagnosis of primary hyperparathyroidism (pHPT) in a consecutive series of patients with operatively verified disease.

Design and subjects: 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%.

Conclusion: 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.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bone Density
  • Calcium / blood*
  • Female
  • Follow-Up Studies
  • Humans
  • Hyperparathyroidism, Primary / blood*
  • Hyperparathyroidism, Primary / diagnosis*
  • Hyperparathyroidism, Primary / physiopathology
  • Hyperparathyroidism, Primary / surgery
  • Ions
  • Male
  • Middle Aged
  • Parathyroid Hormone / blood*
  • Preoperative Care
  • Reference Values
  • Sensitivity and Specificity
  • Young Adult


  • Ions
  • Parathyroid Hormone
  • Calcium