A quantitative Bence-Jones protein test measures the specific level of abnormal proteins (Bence-Jones proteins) in your urine.
Immunoglobulin light chains - urine; Urine Bence-Jones protein
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.
The test involves only normal urination, and there is no discomfort.
Bence-Jones proteins are a part of regular antibodies, called light chains. Sometimes, when your body makes too many antibodies, the level of light chains also rises. These proteins are relatively small and filtered out by the kidneys. They spill over into the urine.
Your doctor may order this test:
A normal result means no Bence-Jones proteins are found in your urine.
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:
Urine immunofixation is a better test for detecting Bence-Jones proteins.
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.
Perry MC. Plasma cell disorders. In Goldman L, Schafer AI,eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011: chap193.