The Bence Jones protein (BJP) test measures the level of BJP in your urine. These proteins are not present in healthy urine samples. Usually they are a sign of multiple myeloma.
Multiple myeloma is a type of bone marrow cancer. BJP are named for Henry Bence-Jones. He first isolated them in 1847.
Your bone marrow is found in the center of your larger bones. It makes red and white blood cells, as well as platelets. Multiple myeloma is a condition where a type of white blood cell is produced in excess.
Normally white blood cells make many different types of antibodies. They play an important role in your immune system. However, when you have multiple myeloma, things change. One white blood cell line grows out of control. It produces only one type of antibody. Worse, these cells crowd out the normal cells. This leaves your body vulnerable to illness.
Multiple myeloma is most common in patients over 60 years old. Patients can go without symptoms for many years. Once symptoms do appear, they may at first seem to indicate other conditions. Therefore, tests must be used to diagnose multiple myeloma. One such test is the BJP test.
Symptoms of multiple myeloma are caused by the overgrowth of white blood cells. Because myeloma cells take over your bones from the inside out, your bones are more likely to break. If you break a bone while doing an everyday task, your doctor might suspect multiple myeloma.
Other symptoms include:
- kidney problems, caused by antibody build-up
- anemia, which causes fatigue or weakness
- swollen or weak legs
- pain in the ribs or back
- compressed spinal cord or nerves, due to bone fractures
- excessive thirst
- frequent urination or constipation, when bones break down and leave excess calcium in the blood
- recurring infections
- excessive bleeding, even from slight injuries
A combination of these symptoms might signal your doctor to give you a BJP test.
The BJP test is a urine test. The urine must be collected using a “clean-catch.” To perform a clean catch:
- Clean the area around your urethra with the wipe your doctor will provide you.
- Begin to urinate into the toilet.
- Move the collection cup into your urine stream.
- Collect one to two ounces of urine.
- Move the cup away and finish urinating into the toilet.
- Close the cup and return it to the lab.
If you’re collecting a urine sample from an infant, you’ll need a urine collection bag. This plastic bag is placed over the labia or around the penis. Adhesive keeps it in place.
To perform a clean-catch on an infant, you will first need to clean around the baby’s urethra. Then you will attach the bag. The bag is covered with a diaper, as usual. Once the baby has peed, the bag is removed. The urine is poured into a container for transport to the lab.
You do not need to prepare for a BJP test. There are no risks associated with the test.
Bence-Jones proteins are not normally found in urine. If your test comes back positive, you probably have multiple myeloma. Other kinds of cancer may also be associated with a positive test.