Serum immunoelectrophoresis is a test that measures immunoglobulins in the blood. Immunoglobulins are proteins that function as antibodies. There are various types of immunoglobulins. Some some can be abnormal. If you do have these abnormal proteins, this test can also help identify their specific type.

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

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

This test is performed to assess the clonality (monoclonal or polyclonal, meaning derived from one group of cells producing them) of immunoglobulins.

No monoclonal antibodies are detected.

In some malignant disorders (most often multiple myeloma or chronic lymphocytic leukemia) a single clone of lymphocytes produces one type of protein -- a monoclonal immunoglobulin. This is identifiable as monoclonal (all the same type) by immunoelectrophoresis. Some people have monoclonal immunoglobulins, but do not have a malignant disorder.

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

McPherson RA and Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: WB Saunders; 2007.

Hoffman R, Benz Jr. EJ, Shattil SJ, et al., eds. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingston; 2005.