Protein electrophoresis measures the specific proteins in the body by using electrical charge to separate them. Serum proteins are either albumin or they are globulins. Globulins are then further delegated into either gamma globulins or alpha-1, alpha-2, or beta globulins.
The normal ranges for each protein fraction in the serum is as follows;
Albumin: 3.6-5.2 g/dL
Alpha-1: 0.1-0.4 g/dL
Alpha-2: 0.4-1.0 g/dL
Beta: 0.5-1.2 g/dL
Gamma: 0.6-1.6 g/dL
SPE is useful in the diagnosis of Multiple Myeloma or Waldenstrom macroglobulinemia which presents as a characteristic elevation in the gamma globulin peaks. It can also be used to help diagnose liver diseases, renal diseases, anemia, and even malnutrition.
Based upon which serum protein fraction is either decreased or increased gives evidence to a specific diseases or a group of diseases.
Albumin is produced by the liver and is the most abundant and arguably one of the most important proteins in the body. One of its main functions is to maintain the colloid pressure between the tissues and the bloodstream. Increases in albumin are seen in severe dehydration. They are decreased in malnutrition, liver disease, nephrotic syndrome or severe burns.
The major alpha-1 globulin is alpha-1 antitrypsin, which is produced in the lungs and in the liver. Increases in alpha-1 are seen in inflammatory states and pregnancy. Alpha-1 is decreased in alpha-1 antitrypsin deficiency. Alpha-1 antitrypsin deficiency is used as marker for an increased risk of emphysema.
Alpha-2 globulins include serum haptoglobin, alpha-2-macroglobulin, and ceruloplasmin. Haptoglobin binds to any free hemoglobin in the blood as a result of intravascular hemolysis to prevent its excretion by the kidneys. Ceruloplasmin is the major protein in the body that carries copper which also plays a role in iron metabolism. Increases in alpha-2 are also seen in inflammatory states and nephrotic syndromes. In cases of nephrotic syndromes you will see a decrease in albumin and a compensatory increase in alpha-2. Alpha-2 may also be elevated in hyperthyroidism, steroid use, and oral contraceptives. It is usually decreased in hemolysis and liver disease.
Beta-globulins include transferrin, low-density lipoproteins (LDL) and complement proteins. Transferrin is the molecule that is used to transport dietary iron to the liver, spleen and bone marrow for storage. LDL is the major carrier of cholesterol in the blood. Complement is a branch of the immune system that plays a specific role in the inflammatory response. Beta protein fractions are increased in hyperlipidemia and iron deficiency anemia. It is decreased in malnutrition.
Gamma-globulins encompass the different classes of immunoglobulins. Gamma globulins are increased in either monoclonal or polyclonal gammopathies. It is decreased in agammaglobulinemia and hypogammaglobulinemia. Immunoelectrophoresis is a reflex test that detects the levels of the different immunoglobulins within the gamma-globulin which should be used when there is an abnormal amount of protein detected.
A monoclonal gammopathy is a narrow band increase in the gamma protein fraction that is composed of a single class of immunoglobulins secreted by a malignant clone of plasma cells. It is also known as the M-protein. M-protein is typically representative of a diagnosis of multiple myeloma, but can be detected in other lymphoid malignancies. Its important to understand that absence of the M-protein does not rule out monoclonal gammopathies as sometimes there is not a detectable concentration within the serum. Sometimes this can lead to a false-negative result. More sensitive tests such as a serum immunofixation test should be performed. Multiple myeloma is a monoclonal increase in IgG immunoglobulins. Other monoclonal gammopathies include waldenstrom macroglobulinemia which is an increase in IgM immunoglobulins. Some more common ones are Al amyloidosis and monoclonal gammopathy of undetermined significance (MGUS).
Polyclonal gammopathies are infectious or various inflammatory processes characterized by a broad-based peak in the gamma fraction. This typically represents a polyclonal immunoglobulin increase seen in autoimmune disease, liver diseases, viral/bacterial infections, and various other malignancies.