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

Collect a "clean-catch" (midstream) urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the penis. Women or girls should wash the area between the labia (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 -- the tube that carries urine from the bladder and opens to the outside. 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.

For an infant:

Thoroughly wash the area around the opening of the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, 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, causing an inability to obtain the specimen. The urine is drained into a container for transport back to the health care provider

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

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 urine protein is high and you have other signs that suggest multiple myeloma.

No presence of Bence-Jones proteins is normal.

Bence-Jones proteins are rarely found in urine, but if they are, they are usually associated with multiple myeloma. Less commonly they are present in Waldenstrom's macroglobulinemia, chronic lymphocytic leukemia, or amyloidosis.

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

McPherson RA and Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: WB Saunders; 2007:399-400.

Goldman L, Ausiello D. Cecil Textbook of Medicine. 22nd ed. Philadelphia, Pa: WB Saunders; 2004:658.