Urine immunofixation is a test to look for abnormal proteins in urine.
How the Test is Performed
You will need to supply a clean-catch (midstream) urine sample.
- Clean the area around where urine leaves the body. Men or boys should wipe the head of the penis. Women or girls should wash the area between the lips of the vagina with soapy water and rinse well.
- Allow a small amount to fall into the toilet bowl as you start to urinate. This clears substances that may contaminate the sample. Catch about 1 to 2 ounces (30 to 60 milliliters) of urine in the clean container that you are given.
- Remove the container from the urine stream.
- Give the container to the health care provider or assistant.
For an infant:
- Thoroughly wash the area where the urine exits the body.
- Open a urine collection bag (a plastic bag with an adhesive paper on one end).
- For males, place the entire penis in the bag and attach the adhesive to the skin.
- For females, place the bag over the labia.
- Diaper as usual over the secured bag.
It may take more than one try to get a sample from an infant. An active baby can move the bag, so that the urine goes into the diaper. Check the infant often and change the bag after the urine has been collected. Drain the urine from the bag into the container given to you by your provider.
Deliver the sample to the lab or your provider as soon as possible after it is done.
How to Prepare for the Test
No special steps are necessary for this test.
How the Test will Feel
The test involves only normal urination. There is no discomfort.
Having no monoclonal immunoglobulins in the urine is a normal result.
What Abnormal Results Mean
The presence of monoclonal proteins may indicate:
- Cancers that affect the immune system, such as multiple myeloma or Waldenstrom macroglobulinemia
- Other cancers
Immunofixation is similar to urine immunoelectrophoresis, but it may give more rapid results.
Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, PA: Elsevier Churchill Livingston; 2005:727-33.
Treon SP, Merlini G. Waldenström macroglobulinemia and lymphoplasmacytic lymphoma. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 86.
Review Date 1/20/2015
Updated by: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.