IEP - urine

Alternative names
Immunoglobulin electrophoresis - urine; Gammaglobulin electrophoresis - urine; Urine immunoglobulin electrophoresis; Immunoelectrophoresis - urine

This is a test that detects the presence or absence of immunoglobulins in the urine and assesses the qualitative character (polyclonal vs. monoclonal) of the immunoglobulins.

How the test is performed

Collect a “clean-catch” (midstream) urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the penis. Women or girls need to wash the area between the labia with soapy water and rinse well. As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine, and remove the container from the urine stream. Give the container to the health care provider or assistant.

Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Place a diaper over the infant (bag and all). Check your baby frequently, and remove the bag after the infant has urinated into it. For active infants, this procedure may take a couple of attempts - lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into a container for transport back to the health care provider.

Immunoelectrophoresis is a laboratory technique. Electrical charges are used to separate and identify the various immunoglobulins, using a combination of protein electrophoresis and an antigen-antibody interaction:

  • Protein electrophoresis indicates the presence of immunoglobulins as a group.  
  • Immunoelectrophoresis enhances the ability to identify the specific immunoglobulins through the use of antibodies that only react with the specific proteins of interest.

Specific lab technique: Monospecific (specific for only one antigen) antiserum is overlaid on the zone of the electrophoretogram (the paper graph used with protein electrophoresis), which contains the unidentified protein. The presence of a precipitin band indicates that the antigen is present for the monospecific antiserum used.

How to prepare for the test
Collection of the first morning urine, which is the most concentrated, may be recommended.

If the collection is being taken from an infant, a couple of extra collection bags may be necessary.

How the test will feel
The test involves only normal urination, and there is no discomfort.

Why the test is performed
This test is used to roughly measure the amounts of various immunoglobulins in urine. Most often, this is used as a screening test, particularly in people who have protein in the urine (demonstrated on urinalysis or other test) when urine protein electrophoresis indicates a significant amount of globulin proteins (antibodies).

Normal Values
Normally there is no, or only a small amount, of protein in the urine. When there is protein in the urine, it normally consists primarily of urine albumin.

What abnormal results mean
Immunoglobulin (antibodies) in the urine can result from kidney disorders such as IgA nephropathy or IgM nephropathy. It can also occur in other disorders such as multiple myeloma (a form of cancer). (See also immunoelectrophoresis - serum.)

In some neoplastic disorders (for example, multiple myeloma or chronic lymphocytic leukemia), a single clone of lymphocytes produces one type of immunoglobulin - a monoclonal immunoglobulin. This is identifiable as monoclonal by immunoelectrophoresis. Some people have monoclonal immunoglobulins, but they do not have a neoplastic disorder.

Macroglobulinemia of Waldenstrom is an additional condition under which the test may be performed.

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

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