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Bence-Jones protein - quantitative

Definition

A quantitative Bence-Jones protein test measures the specific level of abnormal proteins (Bence-Jones proteins) in your urine.

Alternative Names

Immunoglobulin light chains - urine; Urine Bence-Jones protein

How the test is performed

A clean-catch (midstream) urine sample is needed.

Men or boys should first wipe clean the head of the penis. Women or girls need to wash the area between the lips of the vagina 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.

In infants, 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 boys, the entire penis can be placed in the bag and the adhesive attached to the skin. For girls, 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. The urine is drained into a container for transport back to the health care provider.

How the test will feel

The test involves only normal urination, and there is no discomfort.

Why the test is performed

Bence-Jones proteins are relatively small and are filtered out by the kidneys. This test is done to help diagnose medical conditions that lead to protein in the urine (proteinuria).

Your doctor may also order this test when your urine protein level is high or if you have other signs of multiple myeloma.

Normal Values

A normal result means no Bence-Jones proteins are found in your urine.

What abnormal results mean

Bence-Jones proteins are rarely found in urine. If they are, it is usually associated with multiple myeloma.

An abnormal result may also be due to Waldenstrom's macroglobulinemia, chronic lymphocytic leukemia, or amyloidosis.

What the risks are

Special considerations

Urine immunofixation is the best test for detecting Bence-Jones proteins.

References

McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: WB Saunders; 2006.

Hoffman R, Benz Jr. EJ, Shattil SJ, et al., eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingston; 2008.