Immunoradiometric assay of parathyrin with polyclonal and monoclonal region-specific antibodies.
In this immunoradiometric assay (IRMA) of parathyrin (PTH) a polyclonal anti-amino-PTH(1-34) is the capture antibody and a radiolabeled monoclonal anti-hPTH(44-68) is the second antibody. Gel filtration of serum from a hyperparathyroid patient yielded only a single peak of PTH, corresponding to the elution position of synthetic PTH(1-84). Healthy elderly individuals (ages 78 +/- 5 y, mean +/- SD, n = 45) had PTH concentrations (21 +/- 13 ng/L) not significantly higher than those from healthy younger (38 +/- 11 y) adults (20 +/- 8 ng/L, n = 94). Assay results agreed well with those obtained with a carboxyl-terminal PTH assay both in normal subjects (r = 0.63, P less than 0.001) and in patients with primary hyperparathyroidism (r = 0.59, P less than 0.001). Both assays equally discriminated patients with surgically confirmed primary hyperparathyroidism from normal individuals, but the PTH(1-84) IRMA also allowed a nearly absolute discrimination between normal subjects and patients with primary hypoparathyroidism (undetectable serum PTH in 18 of 21 cases) and secondary hypoparathyroidism (caused by hypercalcemia that was caused by a malignant tumor, PTH 1.3 +/- 1.3 ng/L, n = 32). Moreover, the PTH(1-84) IRMA is more sensitive (detection limit in serum, 0.8 ng/L) and easier and quicker to perform than the carboxyl-terminal assay.
Laboratorium voor Experimentele Geneeskunde en Endocrinologie, Katholieke Universiteit Leuven, Belgium.
R
R
Bouillon
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W
Coopmans
D E
DE
Degroote
D
D
Radoux
P H
PH
Eliard
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D002850:Chromatography, Gel; D003937:Diagnosis, Differential; D000939:Epitopes / Q000032:analysis*; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood; D007011:Hypoparathyroidism / Q000097:blood; D015592:Immunoradiometric Assay; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood; D012016:Reference Values
D000911:Antibodies, Monoclonal; D000939:Epitopes; D010281:Parathyroid Hormone; D010446:Peptide Fragments