SERUM/URINE ELECTROPHORESIS

CLINICAL UTILITY:

Numerous diseases and conditions are associated with increases or decreases of the serum proteins. By utilizing agarose electrophoresis (AEP), a high degree of separation of the serum proteins and resolution into distinct bands is achieved. After electrophoresis, the lab reports protein concentration and patterns. Serum protein electrophoresis is used as a screening test, particularly for detecting patterns associated with hepatic or renal disease, immunodeficiencies, or monoclonal gammopathies. In order to quantify specific proteins, however, further testing by other methods is necessary. Immunofixation is the follow-up method used in our lab for identifying monoclonal components and Bence Jones proteins.

Among the patterns most readily recognized as abnormal are those found in hepatic cirrhosis (polyclonal gammopathy), nephrotic syndrome, acute phase reaction, hypogammaglobulinemia, monoclonal gammopathy, and protein-losing enteropathy.

The primary uses of urine electrophoresis are in screening for and quantifying Bence Jones protein as a means of monitoring therapy, and in detecting the selectivity of proteinuria. The pathological conditions associated with proteinuria include a variety of renal diseases.

METHOD DESCRIPTION:

The principle utilized in electrophoresis is that proteins can be separated according to molecular charge and size, the degree of separation being influenced by the support medium strength of charge, ionic strength and pH of the buffer system. The system used in this lab is high resolution electrophoresis in agarose gel.

Following electrophoresis, the gel is stained and the intensity of the bands is measeured with a densitometer. Additionally, each gel is reviewed to interpret the pattern visually. If a monoclonal component is present, quantification is performed on the densitometer. For quantification of Bence Jones protein in urine, a 24-hour urine sample is required. To identify the monoclonal component in serum, or the Bence Jones protein in urine, an immunofixation is suggested. (Order Serum Protein Electrophoresis Reflexive Panel for automatic follow-up on serums, or Bence Jones ID for identification of Bence Jones protein in urine.) Urine protein electrophoresis is done on concentrated urine, with the amount of proteinuria determining the degree to which the urine specimen is concentrated. Therefore we routinely request relatively large volumes of urine specimens.

REFERENCE RANGE:

Serum: Total Protein:6.0 - 8.2 g/dl

Urine: No spike

SPECIMEN REQUIREMENTS:

Serum: 0.3 ml serum (Same aliquot can be used for Immunofixation.) Refrigerate.
Urine: 25.0 ml urine. Refrigerate. 24-hour specimen required for quantification of Bence Jones Protein.