Serum globulin electrophoresis is a laboratory test that looks at proteins called globulins in the blood.

See also:

• Immunoelectrophoresis - serum
• Protein electrophoresis - serum

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to swell with blood.

A needle is inserted into the vein, and the blood is collected in an airtight vial or a syringe. During the procedure, the band is removed to restore blood flow. Once the blood has been collected, the needle is removed. The puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a small glass tube (pipette), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if bleeding continues.

Electrophoresis is a laboratory technique. The fluid part of blood (serum) is placed on specially treated paper and exposed to an electric current. The proteins move on the paper (migrate) to form bands that show the amount of each protein fraction in relation to the other protein fractions.

Fast for 4 hours before the test. The health care provider may advise you to stop taking drugs that can interfere with the test. DO NOT stop taking any medications without first telling your health care provider.

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is performed to look at globulin proteins in the blood. Identifying the types of globulins (globulin electrophoresis) can help diagnose certain disorders.

Proteins are made from amino acids and are important parts of all cells and tissues. There are many different kinds of proteins in the body with many different functions. Examples of proteins are enzymes, some hormones, hemoglobin (oxygen transport), LDL (cholesterol transport), fibrinogen (blood clotting), collagen (structure of bone and cartilage), and immunoglobulins (antibodies).

Blood is made up of red blood cells, white blood cells, and a liquid called plasma. Plasma is made of serum and clotting proteins. Serum proteins include albumin (the main protein) and globulins.

Globulins are roughly divided into alpha, beta, and gamma globulins. These can be separated and measured in the laboratory by techniques called electrophoresis and densitometry. The gamma fraction includes the various types of antibodies (immunoglobulins M, G, and A).

• Serum globulin: 2.0 to 3.5 g/dL
• IgM component: 75 to 300 mg/dL
• IgG component: 650 to 1850 mg/dL
• IgA component: 90 to 350 mg/dL

Increased gamma globulin proteins may indicate:

• Multiple myeloma
• Chronic inflammatory disease (for example, rheumatoid arthritis and SLE)
• Hyperimmunization
• Acute infection
• Waldenstrom's macroglobulinemia

• Excess bleeding
• Fainting or feeling lightheaded
• Blood pooling under the skin (hematoma)
• Infection
• Many needle sticks to find veins

Drugs that can affect the measurement of serum proteins include chlorpromazine, corticosteroids, isoniazid, neomycin, phenacemide, salicylates, sulfonamides, and tolbutamide.

McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders; 2006.

Hoffman R, Benz E, Shattil S, Furie B, Cohen H. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingstone; 2004.