Quantitative Bence-Jones protein test

Definition

This test measures the level of abnormal proteins called Bence-Jones proteins in the urine.

Alternative Names

Immunoglobulin light chains - urine; Urine Bence-Jones protein

How the Test is Performed

A clean-catch urine sample is needed. The clean-catch method is used to prevent germs from the penis or vagina from getting into a urine sample. To collect your urine, the health care provider may give you a special clean-catch kit that contains a cleansing solution and sterile wipes. Follow instructions exactly so that the results are accurate.

The sample is sent to the lab. There, one of many methods is used to detect Bence-Jones proteins. One method, called immunoelectrophoresis, is the most accurate.

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 a part of regular antibodies called light chains. These proteins are not normally in urine. Sometimes, when your body makes too many antibodies, the level of light chains also rises. Bence-Jones proteins are small enough to be filtered out by the kidneys. The proteins then spill into the urine.

Your provider may order this test:

• To diagnose conditions that lead to protein in the urine
• If you have a lot of protein in your urine
• If you have signs of a blood cancer called multiple myeloma

Normal Results

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:

• An abnormal buildup of proteins in tissues and organs (amyloidosis)
• Blood cancer called chronic lymphocytic leukemia
• Lymph system cancer (lymphoma)
• Buildup in the blood of a protein called M-protein (monoclonal gammopathy of unknown significance; MGUS)
• Chronic renal failure

Risks

There are no risks with this test.

References

Chernecky CC, Berger BJ. Protein electrophoresis – urine. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, PA: Elsevier; 2013:920-923.

Riley RS, McPherson RA. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. Philadelphia, PA: Elsevier; 2017:chap 28.