Immunofixation - urine
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.
For an infant:
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.
Why the Test is Performed
This test is most often used to check for the presence of certain proteins called monoclonal immunoglobulins. These proteins are linked to multiple myeloma and Waldenström macroglobulinemia. The test is also done with a blood test to check for a monoclonal immunoglobulin in the serum.
Having no monoclonal immunoglobulins in the urine is a normal result.
What Abnormal Results Mean
The presence of monoclonal proteins may indicate:
Immunofixation is similar to urine immunoelectrophoresis, but it may give more rapid results.
McPherson RA, Riley RS, Massey HD. Laboratory evaluation of immunoglobulin function and humoral immunity. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 46.
Treon SP, Castillo JJ, Hunter ZR, Merlini G. Waldenström macroglobulinemia/lymphoplasmacytic lymphoma. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 87.
Review Date: 1/10/2019
Reviewed By: Gordon A. Starkebaum, MD, MACR, ABIM Board Certified in Rheumatology, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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