Immunonephelometric quantification of specific urinary proteins versus a simple electrophoretic method for characterizing proteinuria.
OBJECTIVE
The quantification of urinary proteins presenting different molecular sizes is useful in characterizing a proteinuria. We assessed the performance of an electrophoretic system, the Hydragel Urine Profile, which allows firstly the identification of proteinuria and secondly a qualitative detection of monoclonal free light chains (FLC).


METHODS
Initially, the proteinuria was characterized on 127 pathological urines by quantifying albumin, a1microglobulin, immunoglobulins G by immunonephelometric quantification technique and the results were compared with the protein pattern obtained by the electrophoretic method. Secondly, we assessed the sensitivity and specificity of this electrophoretic test for the detection and characterization of Bence Jones proteins. FLC were analyzed quantitatively by an immunonephelometric assay and qualitatively by the electrophoretic test in 150 urines.


RESULTS
The agreement between the two methods was good with a percentage of homology for characterizing the proteinuria of 89%. For detecting a monoclonal FLC, the electrophoretic method demonstrated a lesser sensitivity but a higher specificity compared to the immunoassay.


CONCLUSIONS
The Urine Profile kit is a reliable assay that can be used as a screening test to differentiate the type of proteinuria.
Wolff
Fleur
F
Laboratory of Clinical Chemistry, CHU Brugmann, Place Van Gehuchten, 4, 1020 Brussels, Belgium. fleur.wolff@chu-brugmann.be
Willems
Dominique
D
D004586:Electrophoresis / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D011506:Proteins / Q000032:analysis*; D011507:Proteinuria / Q000378:metabolism*; D011933:Reagent Kits, Diagnostic
D011506:Proteins; D011933:Reagent Kits, Diagnostic