The Bence-Jones protein (BJP) test measures the level of BJP in your urine. Bence-Jones proteins are named for Henry Bence-Jones, a physician and chemist who first isolated them in 1847. These proteins are not present in healthy urine samples and are usually a sign of multiple myeloma. Multiple myeloma is a type of bone marrow cancer that is most common in people who are older than 60 years.
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 your bone marrow makes too much of a type of white blood cell.
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, one white blood cell line grows out of control. It produces only one type of antibody. These cells then crowd out the normal cells. Your body is then vulnerable to illness.
People who have multiple myeloma can go without symptoms for many years. Once symptoms do appear, they may seem to indicate other conditions. Therefore, tests such as the BJP test are necessary to diagnose multiple myeloma.
Symptoms to watch for
Symptoms of multiple myeloma are caused by the overgrowth of white blood cells. Myeloma cells take over your bones from the inside out. This makes your bones more likely to break. If you break a bone while performing an everyday task, your doctor might suspect multiple myeloma.
Other symptoms include:
- kidney problems (caused by antibody buildup)
- 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 (from 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.
You do not need to prepare for a BJP test. There are also no risks associated with the test.
Clean catch procedure
The BJP test is a urine test. The urine must be collected using what’s called a clean catch. Instructions for performing a clean catch are listed below:
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, clean around the baby’s urethra. Then attach the bag. The bag is covered with a diaper, as usual. Once the baby has urinated, remove the bag. Then pour the urine into a container for transport to the lab.
A 24-hour urine test may also be used. In this test, you collect samples of urine over a 24-hour period. When you first wake up in the morning, empty your bladder. You won’t collect a sample this time, but instead note the time. For the next 24 hours, save all voided urine into one container. The sample should be refrigerated throughout the duration of the collection process in order to keep it viable. The collection also includes urine from the second morning.
You then bring your urine to the lab for testing.
Your doctor may ask for a 24-hour test because levels of various substances in your body change during the course of an entire day. By collecting urine over 24 hours, the measured substances can be averaged from the entire day. This helps your doctor evaluate them more accurately than they could from a single, random sample.
It can take anywhere from a few days to two weeks to get your results, depending on the lab and your doctor. Bence-Jones proteins are not normally found in urine, so a positive test indicates that you probably have multiple myeloma. Other kinds of cancer may also be associated with a positive result.
In some instances, an abnormal result may not indicate cancer at all. Amyloidosis is a condition that causes amyloid deposits, which are abnormal buildups of proteins in organs and tissues. Amyloidosis is rare, but it’s similar to multiple myeloma. It can have dangerous long-term effects, including kidney failure, heart muscle damage, and nerve damage.
Monoclonal gammopathy of uncertain significance (MGUS) is another common cause of an abnormal BJP test result. In this condition, an abnormal protein that is produced by white blood cells is found in the blood. While MGUS is not dangerous on its own, its progression can lead to other conditions, including blood cancers.
Because an abnormal test result can also indicate other conditions, your doctor will likely order several different tests before diagnosing you with multiple myeloma. More testing can also help your doctor determine the severity of the myeloma.
Your doctor will order a biopsy of the bone marrow or bone tissue. Major components of the diagnostic criteria for multiple myeloma include:
- presence of myeloma cells
- having 30 percent plasma cells in the bone marrow sample
Other tests your doctor may order before diagnosis include:
- urinalysis, which can evaluate kidney function
- X-rays, MRIs, or CT scans, which can help assess changes in bone structure while revealing any potential tumors or bone lesions
- blood tests, including a serum protein electrophoresis test, which can help your doctor determine how much the disease has advanced
While abnormal results of a BJP test are mostly associated with myeloma, they can indicate several other conditions, including noncancerous ones. Your doctor will use further testing to determine an accurate diagnosis. If myeloma is present, further testing can also help your doctor evaluate the progression. The BJP test is easy and painless to take, so the hardest part will simply be waiting for the results.