Date of Award
Masters of Science (Research)
Ms. Marie English
Dr. Brendan O'Connell
Proteinuria is the excess excretion of protein in the urine and is found in a variety of conditions including renal diseases and neoplastic conditions such as multiple myeloma (MM). The investigation of proteinuria type through the use of electrophoresis is a useful and widely used non-invasive diagnostic tool. The aim of this study was to compare various agarose gel and capillary zone electrophoresis techniques in order to establish a method choice for the separation of protein in routine laboratories. Comparisons were made based on urine monoclonal peak quantification and protein fractions detected. An examination of a capillary zone electrophoresis (CZE) based method for the identification of monoclonal components was also carried out. Random urine samples (n = 88) either underwent mechanical concentration prior to analysis by high resolution (HR) or β1 β2 agarose gel electrophoresis; dialysis centrifugation prior to analysis by CZE or was electrophoresed neat on HR gels. All urines underwent both a Bence Jones Protein (BJP) gel immunofixation screen (gold standard) and a CZE immunosubtraction screen. Statistical comparison, using the laboratory’s existing method of βlβ2 agarose gel electrophoresis as the standard against which other methods were compared, showed that best agreement was seen with the HR gel method utilising neat urine samples. The least association was noted with the CZE method. While very similar results and medians were noted in all three agarose gel based methods (medians = 41.75 g/L, 41.2 g/L and 46.6 g/L), the greatest difference in peak quantification was again seen in the CZE technique with a significantly lower median (median = 29.3 g/L). BJP immunofixation screening revealed a total of 21 urines containing monoclonal (M) components. Of these, 16 were evident on CZE and βlβ2 gel electrophoresis, 18 were detectable with concentrated urine on HR gel and 17 were detectable with neat urine on HR gel. CZE did not detect five of the M-component positive urine samples therefore these samples were incorrectly found to be negative by immunotyping. The CZE immunosubtraction method also mistyped five of the sixteen M-component positive samples it did detect. It appears, based on these findings, that HR gel electrophoresis of neat urine samples followed by BJP immunofixation of any suspected monoclonal components is the most reliable and least technically demanding technique of those examined for the investigation of proteinuria.
Curtin, Anne-Marie, "Urine Protein Electrophoresis: Comparison of Agarose Gel and Capillary Zone Electrophoretic Techniques." (2008). Theses [online].
Available at: https://sword.cit.ie/allthe/175