Bence-Jones protein (quantitative)
Alternative names:
immunoglobulin light chains, urine; urine Bence-Jones protein
How the test is performed:
Child or adult:
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 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.
Infant:
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 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.
Since Bence-Jones proteins are relatively small, they can be filtered by the glomerulus of the nephron. When urine protein is elevated, analysis and other clinical features suggest multiple myeloma, a Bence-Jones proteins test may be ordered. These proteins have an unusual thermal property that allows them to be identified; they precipitate from urine when heated between 45 degrees and 60 degrees C and re-dissolve on boiling. Unequivocal identification is made by immunoelectrophoresis (see Immunoglobulin electrophoresis or Immunofixation).
How to prepare for the test:
Adult:
There is no special preparation.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How the test will feel:
The test involves only normal urination and there is no discomfort.
Why the test is performed:
This test is performed to aid in the diagnosis of disorders that can cause protein in the urine (proteinuria).
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