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Optimal discrimination of mild hyperparathyroidism with total serum calcium, ionized calcium and parathyroid hormone measurements

Benson, L; Ljunghall, S; Groth, T; Falk, H; Hvarfner, Andreas LU ; Rastad, J; Wide, L and Akerstrom, G (1987) In Uppsala Journal of Medical Sciences 92(2). p.147-176
Abstract
The serum concentrations of calcium, albumin and parathyroid hormone (PTH) and the plasma levels of ionized calcium were determined in 124 healthy subjects, 89 patients with primary hyperparathyroidism (HPT), 23 of whom had the syndrome of multiple endocrine neoplasia type 1 (MEN-1) and 43 patients who had hypercalcaemia of other causes than HPT (non-HPT), in most cases due to widespread malignancies. The total serum calcium was corrected for the serum albumin concentration (CaM). Healthy females over the age of 50 had higher CaM, than younger females and the women of all ages also had, higher serum PTH levels than males. For all study groups both the intra- and inter-diurnal variations were small for all the studied variables.... (More)
The serum concentrations of calcium, albumin and parathyroid hormone (PTH) and the plasma levels of ionized calcium were determined in 124 healthy subjects, 89 patients with primary hyperparathyroidism (HPT), 23 of whom had the syndrome of multiple endocrine neoplasia type 1 (MEN-1) and 43 patients who had hypercalcaemia of other causes than HPT (non-HPT), in most cases due to widespread malignancies. The total serum calcium was corrected for the serum albumin concentration (CaM). Healthy females over the age of 50 had higher CaM, than younger females and the women of all ages also had, higher serum PTH levels than males. For all study groups both the intra- and inter-diurnal variations were small for all the studied variables. Discriminant function and optimal discriminatory limits were calculated with the help of computer programs. A consideration of all the individuals in the discriminant analysis, revealed that measurements of CaM alone separated most HPT patients both from the healthy subjects and from the non-HPT patients. However, when only those who had borderline values (defined as CaM between 2.45 and 2.75 mmol/l) were included it turned out that measurements of ionized calcium markedly improved the delineation of mild HPT from the healthy subjects and that, in addition, PTH measurements helped to exclude those with non-HPT hypercalcaemia. The optimal discriminatory levels of serum calcium were calculated as the levels which caused the minimum loss in terms of misclassification when attention was paid to the relative importance of false positive to false negative classifications and to the prevalence of HPT. The optimal discriminatory level for serum calcium for a weighting ratio between false positive to false negative of 1:1, and a prevalence of HPT of 1%, was calculated to be 2.68 mmol/l and for a prevalence of 50% 2.56 mmol/l. In the latter situation a weighting ratio of 10:1 for false positive to false negative gave a level of 2.63 mmol/l while a weighting ratio of 1:10 corresponded to an optimal discriminatory level of 2.47 mmol/l. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Uppsala Journal of Medical Sciences
volume
92
issue
2
pages
147 - 176
publisher
Taylor & Francis
external identifiers
  • pmid:2889282
  • scopus:0023627599
ISSN
0300-9734
language
English
LU publication?
no
id
8a8c5dd1-f581-4767-9067-fe535f9cb29b (old id 1103978)
date added to LUP
2008-08-08 17:18:22
date last changed
2017-08-06 03:32:45
@article{8a8c5dd1-f581-4767-9067-fe535f9cb29b,
  abstract     = {The serum concentrations of calcium, albumin and parathyroid hormone (PTH) and the plasma levels of ionized calcium were determined in 124 healthy subjects, 89 patients with primary hyperparathyroidism (HPT), 23 of whom had the syndrome of multiple endocrine neoplasia type 1 (MEN-1) and 43 patients who had hypercalcaemia of other causes than HPT (non-HPT), in most cases due to widespread malignancies. The total serum calcium was corrected for the serum albumin concentration (CaM). Healthy females over the age of 50 had higher CaM, than younger females and the women of all ages also had, higher serum PTH levels than males. For all study groups both the intra- and inter-diurnal variations were small for all the studied variables. Discriminant function and optimal discriminatory limits were calculated with the help of computer programs. A consideration of all the individuals in the discriminant analysis, revealed that measurements of CaM alone separated most HPT patients both from the healthy subjects and from the non-HPT patients. However, when only those who had borderline values (defined as CaM between 2.45 and 2.75 mmol/l) were included it turned out that measurements of ionized calcium markedly improved the delineation of mild HPT from the healthy subjects and that, in addition, PTH measurements helped to exclude those with non-HPT hypercalcaemia. The optimal discriminatory levels of serum calcium were calculated as the levels which caused the minimum loss in terms of misclassification when attention was paid to the relative importance of false positive to false negative classifications and to the prevalence of HPT. The optimal discriminatory level for serum calcium for a weighting ratio between false positive to false negative of 1:1, and a prevalence of HPT of 1%, was calculated to be 2.68 mmol/l and for a prevalence of 50% 2.56 mmol/l. In the latter situation a weighting ratio of 10:1 for false positive to false negative gave a level of 2.63 mmol/l while a weighting ratio of 1:10 corresponded to an optimal discriminatory level of 2.47 mmol/l.},
  author       = {Benson, L and Ljunghall, S and Groth, T and Falk, H and Hvarfner, Andreas and Rastad, J and Wide, L and Akerstrom, G},
  issn         = {0300-9734},
  language     = {eng},
  number       = {2},
  pages        = {147--176},
  publisher    = {Taylor & Francis},
  series       = {Uppsala Journal of Medical Sciences},
  title        = {Optimal discrimination of mild hyperparathyroidism with total serum calcium, ionized calcium and parathyroid hormone measurements},
  volume       = {92},
  year         = {1987},
}