Protein Electrophoresis, Random Urine

A serum protein electrophoresis should be reviewed concurrently if one has not been recently studied. In nonselective glomerular proteinuria, the urine electrophoretic pattern is often a nonspecific one which may be called “mirror image” to that of the serum. Contamination of the urine with blood can give a similar pattern. With selective glomerular permeability, albumin, α₁-proteins, and transferrin are the predominant proteins identified on the urine protein electrophoresis, with a relative absence of heavier molecular weight proteins (ie, α₂-macroglobulin and immunoglobulins). With tubular proteinuria, low molecular weight proteins (α₂- and β₂-microglobulins) are predominant, with trace amounts of albumin. So called “overflow proteinuria” occurs when low molecular weight proteins are filtered through the glomerulus in increased amounts.