Testing for multiple myeloma
Multiple myeloma patients often feel overwhelmed by the number of tests they must undergo, but it is important to remember that all of these tests help a doctor forecast the course and outcome of the disease and provide the best possible care based on the results.
These tests give our doctors key information on the genetic make-up of the myeloma cells and the extent to which the myeloma has progressed.
These multiple myeloma tests are typically ordered:
Bone marrow examination
A bone marrow examination determines whether myeloma cells are in the bone marrow, how many there are, and how much damage they are doing to the normal bone marrow structure.
There are two parts to a bone marrow exam: aspiration and biopsy. During a bone marrow aspiration, a thin needle is inserted through the bone to remove a liquid sample of bone marrow tissue. During a bone marrow biopsy, a larger needle is used to remove a small piece of bone with the marrow inside. These tests are usually done on the back of the hipbone, but may also be done on the front of the hip bone or on the breastbone.
The samples collected during the bone marrow exam will also be used for sophisticated tests such as the following:
- Studies the structure of chromosome material
- FISH (fluorescent in situ hybridization)
- Searches for the presence or absence of specific features in DNA
- Gene array analysis
- Discovers which genes are abnormally expressed in the cells in an effort to determine which forms of myeloma a patient has, how well he or she may respond to therapy, and how long the response will last.
Imaging studies are used to locate and examine any bone destruction that may be caused by myeloma. The goal is to detect fractures before they become problematic.
The types of imaging studies include the following:
- MRI (Magnetic Resonance Imaging) scan
- Uses magnets and a computer to produce exceptionally clear and detailed images of the bones and the bone marrow. MRI can pinpoint the location and volume of myeloma cells.
- PET (Positron Emission Tomography)/CT scan
- Shows both functional and anatomical information. The PET exam shows how cells are utilizing nutrients like sugar, since we know that cancer cells absorb sugar more rapidly and at a higher rate. The more uptake of sugar in the myeloma cells, the more rapid the myeloma cells grow. The CT scan uses x-rays and computers to see inside your body to see if the lesion that picks up sugar is associated with bone destruction (lytic lesion). If that is the case, it is almost surely a myeloma lesion.
Blood and urine tests
Blood tests are necessary to measure white cell and platelet counts, check calcium levels, assess kidney and liver function, and to evaluate for anemia.
The presence of various abnormal proteins in the blood and urine, especially monoclonal protein (or M-protein), are examined through electrophoresis. Myeloma is characterized in most patients by a significant increase in M-protein and this can be followed to evaluate the effectiveness of treatment.
As the disease becomes more aggressive, though, myeloma cells may produce less or even no M-protein.
Other tests that help show how aggressive myeloma is include the following:
- CRP, or C Reactive Protein
- A high level of this protein in the blood is often seen in myeloma patients and increases with active disease.
- Beta-2 (b2) micro globulin
- Increased levels of this protein found on the surface of myeloma cells indicate more advanced myeloma. High levels of this protein are also found in patients with kidney damage, irrespective of how many myeloma cells are present. Both kidney damage and extent of the disease are indicators of a worse prognosis, so this test is especially important for newly-diagnosed patients. It is less useful once patients are on treatment, except for detection of early recurrence of myeloma.
- Light chains (or Bence Jones protein) test
- Examining light chains in urine is important because the protein can cause renal injury or kidney failure if found in large amounts.
- Quantitive immunoglobulins
- This test is used to measure the levels of different types of antibodies.
- LDH (lactate dehydrogenase)
- A high level of this enzyme indicates extensive myeloma.
- Serum free light chains
- This measures the amount of light chains not bound to heavy chains. The more aggressive the myeloma, the higher the level of free light chains will be. In addition to looking at the relevant free light chain, it is also important to look at the ratio of the two light chains. If the involved free light chain increases but the ratio remains the same, it is unlikely that the disease is worsening.