Protein Electrophoresis, Serum

The serum protein electrophoresis (SPE) test is used to measure specific proteins like albumin, globulin, etc and to identify some abnormal proteins in the blood or body fluids. Proteins are made up of amino acids and carry a positive or a negative electrical charge. They move in fluid when placed in an electrical field, due to their electrical charge. Serum protein electrophoresis (SPE) separates the proteins in the blood serum on the basis of their size, shape and charge, in the electrical field. Blood contains two major protein albumin and globulin, which carry substances through the bloodstream. Serum protein electrophoresis, separates these two groups into five smaller groups or fractions. They include albumin, Alpha-1 globulin, Alpha-2 globulin, Beta globulin and Gamma globulin. Albumin is the major protein that prevents blood from leaking out of the blood vessels. It is also a transport protein which carries some drugs and other substances through the blood. Albumin is important for tissue growth and healing. Alpha-1 globulin is a high-density lipoprotein (HDL) which includes alpha 1 antitrypsin, transcortin, etc in this fraction. Alpha-2 globulins include haptoglobin, alpha-2 macroglobulin, etc. Beta globulin proteins carry substances, such as iron, through the bloodstream and help fight infection. These include Transferrin, beta lipoprotein, etc. Gamma globulin are also called antibodies or Immunoglobulins. They are of 5 classes ûIgG, IgA, IgM, IgE, IgD. They prevent and fight infections by binding to the foreign substances, such as bacteria or viruses and ensure they are destroyed by the immune system. Each of these five protein fractions move at a different rate in an electrical field depending on their size, shape and charge and form a specific pattern. This pattern helps in the identification of certain diseases.

1. What are the other uses of electrophoresis?

Electrophoresis may be used any time a separation of molecules is desired. DNA electrophoresis is used to study the genetic makeup of plants, animals, and humans. Hemoglobin electrophoresis is used to screen and diagnose hemoglobinopathies. Urine electrophoresis is used to detect Bence jones proteins seen in multiple myeloma.

2. If a person has an abnormal monoclonal immunoglobulin in his blood, does it mean that he has multiple myeloma or some other type of cancer?

Not necessarily. Abnormal Monoclonal protein production is most commonly due to monoclonal gammopathy of undetermined significance (MGUS) which has a benign course, but needs to be monitored regularly with a serum protein electrophoresis test, or as a free light chain test, depending on which monoclonal protein is being abnormally produced. Some of these cases may develop multiple myeloma after several years.

3. What are free light chains of immunoglobulins?

Immunoglobulin molecules have four protein chains: two identical light chains, either kappa or lambda light chains, and two identical heavy chains which are of several types. Immunoglobulins are produced by plasma cells in the bone marrow. Each plasma cell produces only a particular type of immunoglobulin. These plasma cells use the protein chains as component parts to assemble immunoglobulins. The abnormal levels of light chains (kappa and lambda) can be detected in the blood and/or urine with a free light chain test, and ratios between the kappa and lambda free light chains.

4. What are Bence Jones proteins?

Bence jones proteins are free immunoglobulin light chains that are found in the urine. They are seen in multiple myeloma etc.

5. What is Tamm-Horsfell protein?

The Tamm-Horsfell protein is a glycoprotein that is normally seen in urine. It is commonly called uromodulin, which is produced by the kidney and is the most abundant protein in normal urine.

6. What is immunofixationelectrophoresis used for?

IFE is done when serum protein electrophoresis has indicated raised immonoglobulin levels. IFE is frequently used to diagnose multiple myeloma, a disease of the bonemarrow.