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Hypercalcemia and elevated concentration of vitamin D: A case report too easy to be true.

Authors :
Belaidi N
Georges A
Lacroix I
Croisonnier A
Ducros V
Souberbielle JC
Corcuff JB
Source :
Clinica chimica acta; international journal of clinical chemistry [Clin Chim Acta] 2016 Jun 01; Vol. 457, pp. 123-4. Date of Electronic Publication: 2016 Apr 16.
Publication Year :
2016

Abstract

Background: Endogenous (heterophile, human anti-animal …) antibodies are a known cause of interference in immunoassays.<br />Case Report: A patient with hypercalcemia and low PTH levels was investigated. The serum 25OH vitamin D (25OHD) concentration was above the analytical range of the automated analyser (>150ng/mL) but serum dilutions were not linear. A myeloma-related monoclonal peak of immunoglobulin G (30g/L) was found.<br />Results: Alternative 25OHD assays (RIA, automated analysers, mass spectrometry) all found concentrations <25ng/mL. NabTM columns (Thermo Scientific) eliminated the endogenous immunoglobulin from the serum thus allowing the initial analyser to provide correct results.<br />Discussion and Conclusion: The potentially misleading point was that the apparent very high 25OHD levels were concomitant with hypercalcemia and low PTH levels thus mimicking vitamin D intoxication. Identifying assay interferences requires clinical awareness but, when suspected, one should be aware that technical tools or alternate assays are available to correct some interferences, including monoclonal immunoglobulins.<br /> (Copyright © 2016 Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
1873-3492
Volume :
457
Database :
MEDLINE
Journal :
Clinica chimica acta; international journal of clinical chemistry
Publication Type :
Academic Journal
Accession number :
27095608
Full Text :
https://doi.org/10.1016/j.cca.2016.04.013