Myeloma - Diagnosis
Blood tests that administered in some routine medical examinations include a measurement of blood proteins, such as albumin. A lab test result showing an unusually high level of total protein might lead to further blood and marrow tests and to the diagnosis of myeloma.
The diagnosis of myeloma depends on three principal findings:
- Increased numbers of malignant plasma cells (myeloma cells) are found in a bone marrow aspirate and biopsy (usually taken from the hip bone). Bone marrow that contains more than 10 percent plasma cells suggests myeloma.
- Intact monoclonal immunoglobulins or immunoglobulin light chains (Bence Jones protein) are found in the blood and/or urine.
- An imaging study identifies bone thinning or holes or fractures in the bones that characterize myeloma. Magnetic resonance imaging (MRI), especially of the spine, can detect bone changes earlier than conventional x-ray studies, and in some cases, so can positron emission tomography (PET) scanning.
Sometimes, myeloma is not suspected until blood tests for other routine examinations indicate an elevated globulin level. This may lead to additional tests, especially if you have no symptoms. If myeloma is suspected, your doctor will test your blood a second time in order to confirm a diagnosis. Your blood is sent to a lab for a complete blood count (CBC). This can reveal whether myeloma cells are affecting normal blood cell development.
Your doctor also checks your blood for:
- Calcium levels. Increased levels can mean that calcium has moved out of your bones and into your bloodstream, which puts your kidneys at risk for damage.
- Protein levels. Your doctor can estimate the size and growth rate of myeloma tumors by measuring the levels of certain proteins.
- Urea nitrogen and creatinine levels. These proteins are measured to test your kidney function.
Your doctor tests your urine in a urinalysis for Bence Jones protein, which can indicate the presence of myeloma. Bence Jones proteins can impact kidney function and be an indicator of the extent of the disease.
Bone marrow testing involves two steps performed simultaneously in a physician's office or hospital. The first step is a bone marrow aspiration (performed to remove a liquid marrow sample) and the second step is a bone marrow biopsy (performed to remove a small portion of bone filled with marrow). Your doctor may choose to also take bone marrow samples during your treatment to assess how you are responding to therapy.
Serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) tests identify the presence of abnormal proteins, absence of normal proteins, and the increases and/or decreases of different proteins in serum or urine. These tests are usually ordered to detect and identify increased production of specific proteins (immunoglobulins) and to measure each of the five types of immunoglobulins (IgG, IgA, IgM, IgE, or IgD). The tests usually should be repeated at regular intervals to track the course of the disease and assess the effectiveness of treatment.
You might need to have an X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI) scan, or a positron emission tomography (PET) scan. These tests are used to look for bone damage in the form of thinning, holes, or fractures.
It is not only important for your doctor to be experienced in treating patients with myeloma, but also for him or her to work in consultation with a myeloma specialist called a hematologist oncologist. Upon examining samples of your blood and bone marrow, a hematopathologist will confirm a diagnosis, help identify the myeloma stage, and looks for certain changes in your chromosomes. Using the information he or she received from your hematopathologist’s analysis, your doctor will determine the direction your treatment will take.
The hematopathologist performs a cytogenetic analysis to identify certain changes in chromosomes and genes. This may involve a G-banding karyotyping test or a Fluorescence in situ hybridization (FISH) test. Common cytogenetic abnormalities (damage to DNA in chromosomes) that affect myeloma cells include:
- Deletion of chromosome 13.
- Translocation of chromosome 14.
- An abnormality or loss of the short arm of chromosome 17.
When your physician has confirmation of the diagnosis and the results of the diagnostic testing, it is possible to discuss the stage of your disease and how that impacts treatment recommendations. If you are diagnosed with myeloma, you will need to undergo additional testing during and after treatment to see how your myeloma is responding to therapy.
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