Urine immunofixation is a test to look for proteins in urine.

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 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.

I 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 health care provider.

Deliver the sample to the lab or your health care provider as soon as possible after it is done.

No special steps are necessary for this test.

The test involves only normal urination. There is no discomfort.

This test is most often used to check the levels of certain proteins (called monoclonal immunoglobulins). These proteins are linked to multiple myeloma and Waldenstrom's macroglobulinemia.

No presence of monoclonal immunoglobulins is normal.

The presence of monoclonal proteins may indicate:

• Immune system disorders such as multiple myeloma or Waldenstrom's macroglobulinemia
• Cancer

Immunofixation is similar to urine immunoelectrophoresis, but it may give more rapid results.

McPherson RA, 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.22nd ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 46

McPherson RA and Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods.21st ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 46.

Hoffman R, Benz Jr. EJ, Shattil SJ, et al., eds. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingston; 2005:727-33.