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Monoclonal gammopathy missed by capillary zone electrophoresis
-
Christof Schild
,
Florence Egger
Veröffentlicht/Copyright:
17. Mai 2011
Abstract
Background: Serum protein electrophoresis is used as a screening test for monoclonal gammopathies. Here, we present a case of a high-concentration monoclonal immunoglobulin (M-protein) that was missed by serum protein electrophoresis on a Capillarys 2 capillary zone electrophoresis system. The aim of our study was to identify the reason for the failure of the system to detect the M-protein.
Methods: M-protein solubility was examined in response to temperature, pH, ionic strength, the chaotropic agent urea and the reducing agent 2-mercaptoethanol.
Results: Precipitation of the M-protein was not cold-induced, but solubility decreased at pH 8.5 or higher, when the pH approached the apparent isoelectric point. The M-protein also precipitated in alkaline Capillarys 2 electrophoresis buffer (pH 10), which was the reason for the false-negative electrophoresis result. Precipitation of the M-protein was not related to the ionic strength of the buffer. Solubility improved in presence of urea. Pre-treatment of serum with 2-mercaptoethanol revealed the missing M-protein peak of 36 g/L on the electropherogram.
Conclusions: This case shows that insolubility of M-proteins in alkaline buffer is one possible cause of false-negative results on capillary zone electrophoresis systems. False-negative results should be considered, especially when accompanying laboratory results are inconsistent with the electropherogram.
Received: 2010-11-15
Accepted: 2011-2-14
Published Online: 2011-05-17
Published in Print: 2011-07-01
©2011 by Walter de Gruyter Berlin Boston
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Schlagwörter für diesen Artikel
capillary zone electrophoresis;
gammopathy;
monoclonal components;
monoclonal proteins
Artikel in diesem Heft
- Editorial
- Method comparison: where do we draw the line?
- Review
- Current role of liquid chromatography coupled to mass spectrometry in clinical toxicology screening methods
- Minireview
- Molecular diagnostics for pharmacogenomic testing of fluoropyrimidine based-therapy: costs, methods and applications
- Opinion Paper
- Preanalytical quality improvement: from dream to reality
- Point
- Towards more complete specifications for acceptable analytical performance – a plea for error grid analysis
- Counterpoint
- Closing the brain-to-brain loop in laboratory testing
- General Clinical Chemistry and Laboratory Medicine
- Harmonization of growth hormone measurements with different immunoassays by data adjustment
- Comparison of the results from two different External Quality Assessment Schemes supports the utility of robust quality specifications
- High-throughput LC-MS/MS method for monitoring sirolimus and everolimus in the routine clinical laboratory
- Performance of the Roche Total Mycophenolic Acid® assay on the Cobas Integra 400®, Cobas 6000® and comparison to LC-MS/MS in liver transplant patients
- Diagnostic efficiency of truncated area under the curve from 0 to 2 h (AUC0–2) of mycophenolic acid in kidney transplant recipients receiving mycophenolate mofetil and concomitant tacrolimus
- Good performance of an immunoassay based method for nevirapine measurements in human breast milk
- Measurement of plasma amino acids by Ultraperformance® Liquid Chromatography
- Interchangeability of blood gas, electrolyte and metabolite results measured with point-of-care, blood gas and core laboratory analyzers
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