Reference Values for the Five Electrophoretic Serum Protein Fractions in Caucasian Children by Capillary Zone Electrophoresis

IntroductionIn clinical laboratories, capillary zone electrophoresis(CZE) has emerged as a novel technique for the rapidand effective separation of serum proteins (1, 2). CZEhas the advantage of automation, improved precision,and a faster turn-around time.CZE uses ultraviolet detection at 214 nm for directprotein quantification through the quantification of thepeptide bonds, whereas with conventional methods,protein quantification is based on dye binding. This dif-ference between CZE and conventional methods withrespect to the technique that is used to quantify proteinhas an impact on the reference range. For example,when compared to agarose or cellulose acetate elec-trophoresis, CZE gave substantially higher referenceintervals for the α1-globulin fraction (2). This discrep-ancy is related to the fact that the high sialic acid con-tent of α1-acid glycoprotein interferes with the bindingof dyes used to quantify this protein fraction.Although several studies have reported referenceranges for CZE in healthy adults (2–6), no such data isavailable for children. Studies in children using con-ventional zone electrophoresis (7, 8) showed age-de-pendent changes in the reference range.In children there is little need to perform electrophore-sis for the diagnosis and monitoring of myeloma, whichis the main indication for performing serum proteinelectrophoresis. However, serum protein electrophoresis is also useful for assessing overall plasma proteinstatus. Although the major serum proteins can be mea-sured by quantitative assays, serum electrophoresis is acheap and valuable initial procedure for detecting ab-normalities of the serum proteins. It is of use in the labo-ratory investigation of acute and chronic inflammatorydiseases, in protein-losing syndromes, and in the detec-tion of protein deficiencies (9, 10). As there is a correla-tion between the sum of the individually measured im-munoglobulins and the electrophoretic γ-globulin level,serum electrophoresis is also of use as an initial screen-ing test for the detection of hypogammaglobulinemiaand of primary immunodeficiency (10–12). It is unusualto find hypogammaglobulinemia if the γ-globulin levelis normal on serum electrophoresis (9).The aim of our study was to establish CZE referenceintervals for the five electrophoretic serum protein fractions in Caucasian children.