To be diagnosed with multiple myeloma, you must meet a specific set of diagnostic criteria. There are many tests that help doctors make this diagnosis, such as lab, bone marrow, and imaging tests.
Multiple myeloma is a type of cancer that affects the white blood cells in bone marrow called plasma cells. These are the cells that produce antibodies to help your body respond to infections.
When cancerous plasma cells — called myeloma cells — begin to grow and divide out of control, they crowd out other blood cells in the bone marrow. They also make abnormal antibodies called M protein that can build up in the body.
If you have symptoms suggestive of multiple myeloma, your doctor can perform a variety of tests to help make a diagnosis.
After taking your medical history and doing a physical exam, lab tests are some of the first tests that will be done to help make a multiple myeloma diagnosis. These tests involve samples of blood and urine.
Blood tests for multiple myeloma
Blood tests for multiple myeloma involve taking a blood sample from a vein in your arm. There are several blood tests that may be done, including:
- Complete blood count: A complete blood count (CBC) looks at the levels of different types of blood cells in a blood sample. If you have multiple myeloma, some of these blood cell counts may be low.
- Blood chemistry: Blood chemistry tests look at a variety of substances present in your blood. Some substances that may have altered levels in multiple myeloma include calcium, albumin, and creatinine.
- Immunoglobulins: An immunoglobulin test looks at the levels of different types of antibodies in the blood. In multiple myeloma, levels of one antibody type may be much higher than others.
- Serum protein electrophoresis (SPEP) and immunofixation: In a serum protein electrophoresis (SPEP) and immunofixation test, a blood sample is placed on a special paper and exposed to an electrical current. This separates the different antibodies in the sample into bands. A healthcare professional can analyze these bands to see if M protein is present.
- Serum-free light chains: This test looks for a component of antibodies, called light chains, in the blood. It can be helpful in detecting potential multiple myeloma when a SPEP and immunofixation test doesn’t find M protein, meaning you may have something called light chain myeloma rather than multiple myeloma.
Your doctor will request that you collect your urine over a 24-hour period. This is called a 24-hour urine sample.
A 24-hour urine sample is used for urine protein electrophoresis (UPEP) and immunofixation. This is done similarly to SPEP and immunofixation, but instead, this test looks for M protein released into your urine as opposed to in the blood.
If you have multiple myeloma, myeloma cells are present in your bone marrow. Taking a sample from the bone marrow can help your doctor look for these myeloma cells.
This involves two types of collection:
- Bone marrow aspiration: A bone marrow aspiration collects a fluid sample, which includes bone marrow cells, from the bone marrow.
- Bone marrow biopsy: A bone marrow biopsy collects a small sample of bone that also contains bone marrow cells.
The samples can be examined under a microscope to look for myeloma cells. If cancer is found, tests can be done to help further characterize it. These look into the size, shape, and number of myeloma cells as well as their genetics.
Imaging tests are also an important part of the diagnostic process. They can help a doctor understand the extent and severity of your multiple myeloma.
The types of imaging tests that may be used include:
- Bone survey: A bone survey is a type of X-ray that looks for damage to your bones that may have happened due to multiple myeloma.
- Computed tomography (CT) scan: A CT scan takes a series of X-ray images of your body.
- Magnetic resonance imaging (MRI) scan: An MRI uses radio waves and strong magnets to make images of the inside of your body.
- Positron emission tomography (PET) scan: A PET scan uses a radioactive dye that’s taken up by cancer cells and can help a doctor see where in your body the cancer is. PET scans are often combined with CT scans (PET/CT scan).
Diagnostic criteria are a set of symptoms, signs, or tests that can help a doctor diagnose a medical condition. In order to be diagnosed with multiple myeloma, both of the following must be true:
- You must have a biopsy-proven plasmacytoma OR have at least 10% of bone marrow made up of cancerous plasma cells.
- You must have at least one of the following multiple myeloma-associated findings:
- low red blood cell counts (anemia)
- poorly functioning kidneys
- high calcium levels in the blood (hypercalcemia)
- bone lesions
- bone marrow where at least 60% of the cells are cancerous plasma cells
- an increase in the levels of one type of light chain that makes it 100 times more common than the other type
It’s important to see a doctor if you have symptoms of multiple myeloma, which can include:
- anemia, which can cause:
- severe fatigue
- easy bruising or bleeding
- frequent infections or infections that are difficult to clear
- bone pain or bones that break easily
- high levels of calcium in the blood, which can lead to:
- peripheral neuropathy
While multiple myeloma might not be the cause of your symptoms, it’s possible that you have another medical condition that needs medical attention.
How common is multiple myeloma?
Multiple myeloma is not a common type of cancer. The
What causes multiple myeloma?
It’s not really clear what causes multiple myeloma. Overall, multiple myeloma happens when genetic changes in plasma cells cause them to become abnormal and start dividing out of control. Genetic changes that lead to cancer can be inherited or acquired.
There are a variety of tests that a doctor uses to diagnose multiple myeloma. In order to be diagnosed with multiple myeloma, you need to meet the diagnostic criteria for it. This is a specific set of symptoms, signs, and tests that help your doctor to diagnose multiple myeloma.
See your doctor if you begin to have symptoms that are suggestive of multiple myeloma. They can order tests to help find out what may be causing your symptoms and determine the proper treatment approach.