Blood and urine tests are needed to determine calcium levels and changes in the level of different abnormal proteins that myeloma produces. In the blood, these proteins are called “paraproteins” and in the urine, they are called “Bence-Jones proteins.” These paraproteins are measured in the blood by a test called serum protein electrophoresis (or SPEP). The Bence-Jones protein is measured in the urine by collecting a 24-hour urine sample and running a urine protein electrophoresis (or UPEP).
If these proteins cannot be detected by serum electrophoresis or by urine electrophoresis, an additional test, called immunofixation (or IFE), is performed to detect even small traces of these abnormal proteins.
Bone Marrow Aspiration
A bone marrow aspiration is used to determine the number of plasma cells present in the bone marrow. Normal bone marrow contains less than 5 percent plasma cells, whereas in myeloma, plasma cells account for more than 30 percent of cells being produced. However, it is important to know that multiple myeloma is considered a “spotty” disease, meaning that you can find a spot in your marrow that is packed with myeloma cells and move a few centimeters away and find a spot that is relative clean and free of myeloma cells.
Myeloma can be present as single or multiple tumors in the bone or soft tissue around the bone. These tumors are called plasmacytomas. Direct biopsy of one of these plasmacytomas usually shows 90-100 percent myeloma cells.
Bone X-rays or surveys will be done to look for lytic lesions or osteoporosis. Other more detailed tests may be required, such as a bone density scan, magnetic resonance imaging (MRI) or positron emission tomography (PET) scan. These tests may find very early or small lytic lesions missed by bone x-rays.
Once multiple myeloma is diagnosed, your doctor will determine the stage of the disease. Staging is a way of determining how much disease is in the body and where it is. The doctor needs this information to decide the best way to treat the cancer. Once staging is determined, it does not change regardless of response to chemotherapy or disease activity.
Multiple myeloma is staged using a system called Durie-Salmon Staging System. The system is based upon the number of bone lesions, the level of protein in the blood and/or urine and the blood calcium level.
Stage I: small amount of myeloma cells
Stage II: intermediate amount of myeloma cells
Stage III: large amount of myeloma cells
In addition, each stage is classified as “A” or "B" depending on kidney function. "A" means there is normal kidney function and “B” means abnormal kidney function. As you would expect, stage IIIB would require more urgent treatment to protect and/or recover kidney function.