serum protein electrophoresis (SPE)
Indications
Reference interval
- serum protein (total): 6.3 - 8.3 g/dL
- serum albumin: 3.5-5.1 g/dL
- serum globulin: 2.5-3.5 g/dL
Clinical significance
The most common abnormality observed by serum protein electro- phoresis is an elevated haptoglobin. Normally, haptoglobin accounts for 25% of the alpha-2 fraction. As an acute phase reactant, haptoglobin becomes elevated nonspecifically in the presence of inflammation or tissue destruction. Other acute phase reactants including alpha-1-acid glycoprotein (orosomucoid) & alpha-1-antitrypsin may also be elevated during acute inflammation.
Alpha-2 macroglobulin normally accounts for 25% of the alpha-2 fraction on serum protein electrophoresis. Due to its large size, alpha-2 macroglobulin is selectively retained in nephrotic syndrome & protein-losing gastroenteropathies.
Beta-1 transferrin normally accounts for 60% of the beta-1 band on serum protein electrophoresis. Low levels occur, along with low levels of albumin, prealbumin, & beta-lipoprotein, in inflammation & malignancy.
Elevation of polyclonal IgA in hepatic cirrhosis gives rise to the characteric beta-gamma bridging observed. IgA normally migrates at the cathodal edge (left side) of the gamma region. With monoclonal gammopathy, large amounts of homogeneous protein migrate as a sharp band on serum protein electrophoresis.