Multiple Myeloma: Diagnosis

Approved by the Cancer.Net Editorial Board, 05/2020

ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of a medical problem. Use the menu to see other pages.

Doctors use many tests to find, or diagnose, cancer. They also do tests to learn if cancer has spread to another part of the body from where it started. If this happens, it is called metastasis. For example, imaging tests can show if the cancer has spread. Imaging tests show pictures of the inside of the body. Doctors may also do tests to learn which treatments could work best.

For most types of cancer, a biopsy is the only sure way for the doctor to know if an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

This section describes options for diagnosing multiple myeloma. Not all tests listed below will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • The type of cancer suspected

  • Your signs and symptoms

  • Your age and general health

  • The results of earlier medical tests

The following tests may be used to diagnose multiple myeloma:

Blood and urine tests. Myeloma cells often secrete the antibody monoclonal immunoglobulin, known as M protein. M protein levels in a patient's blood and urine are used to determine the extent of the disease and to monitor the effectiveness of treatment. In some people, the myeloma cells only secrete part of the antibody, which is called the light chain. The amount of M protein in the blood or urine is measured by serum protein electrophoresis (SPE or SPEP) or urine protein electrophoresis (UPE or UPEP). These tests help to see if the treatment is working and whether the disease is progressing or coming back.

Immunoglobulin levels are measured to help check the amount of antibody levels in the blood. These antibodies are immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM). In multiple myeloma, when the cancer protein level is up, the normal antibody levels are down.

The amount of free light chains in the blood can be measured before the blood is filtered by the kidneys. This test is called a serum free light chain assay. This is a more sensitive test than measuring M protein in the urine, but both are important to measure. When a light chain is found in the urine, it is called the Bence Jones protein.

The levels of serum albumin and serum beta-2 microglobulin (β2-M) are also measured using blood tests. Serum albumin is a blood protein made by the liver that is necessary for maintaining proper blood volume and general health. β2-M is a small protein that plays a role in the body's immune response. These results are important for determining the stage of the myeloma. Blood tests are also used to measure kidney function, calcium levels, and blood cell counts for possible anemia and other low blood counts.

X-ray. An x-ray is a way to create a picture of the structures inside of your body, using a small amount of radiation. X-rays taken as part of the doctor’s evaluation of the patient’s skeletal system are typically the first step in evaluating bones when myeloma is suspected or diagnosed. A x-ray skeletal survey may not find myeloma as early as the more advanced tests described below.

Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. An MRI can show if normal bone marrow has been replaced by myeloma cells or by a plasmacytoma, especially in the skull, spine, and pelvis. A plasmacytoma is a plasma cell tumor growing in bone or soft tissue. The detailed images may also show compression fractures of the spine or a tumor pressing on nerve roots. MRI can also be used to measure the tumor’s size.

Computed tomography (CT or CAT) scan. A CT scan creates a detailed, cross-sectional view that shows any abnormalities or tumors in soft tissues. A computer then combines these pictures into a 3-dimensional image of the inside of the body. It is important to note that the intravenous contrast dye often used for CT scans for other types of cancer is specifically avoided in people with multiple myeloma. Tell the radiologist or the radiology technician about your diagnosis before receiving dye injection into your vein, because this can cause kidney damage in people with myeloma.

Positron emission tomography (PET) or PET-CT scan. A PET scan is usually combined with a CT scan (see above), called a PET-CT scan. But you may hear your doctor refer to this procedure just as a PET scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive sugar substance is injected into the patient’s body. This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body.

Bone marrow aspiration and biopsy. These 2 procedures are similar and often done at the same time to examine the bone marrow. Bone marrow has both a solid and a liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle. This is important for making a diagnosis of myeloma.

A pathologist then analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. The genes in the myeloma are examined by cytogenetics and a special testing called fluorescent in situ hybridization (FISH). Cytogenetics is a type of genetic testing that is used to analyze a cell's chromosomes. These tests determine the genetic makeup of the myeloma and whether it is standard or high risk. Samples can also be examined using genomic sequencing to determine with great accuracy exactly what changes have occurred in the DNA of the cancer cells.

A common site for a bone marrow aspiration and biopsy is the pelvic bone, which is located in the lower back by the hip. The skin in that area is numbed with medication beforehand. This medication is called anesthesia. Other types of anesthesia may also be used to block the awareness of pain.

Fat pad aspirate. If certain M proteins that are misfolded in a particular way are deposited in body tissues, it can cause organs to stop functioning normally. This condition is called amyloidosis. If your doctor suspects you may have amyloidosis, then it may be necessary to take a sample of the abdominal fat pad (the collection of fat around a person's abdomen) to be examined under a microscope, called a biopsy.

Molecular testing of the tumor. Your doctor may recommend running laboratory tests on a tumor and/or bone marrow sample to identify specific chromosomes (cytogenetics), genes (FISH or genomic sequencing; see above), proteins, and other factors unique to the tumor as mentioned above. Results of these tests can help determine your treatment options.

  • Cytogenetics. Cytogenetics, which is the study of genetic changes in cells, and molecular studies may be performed on a tissue sample removed during a biopsy to find out how aggressive the cancer is. In myeloma, the genes in plasma cells are routinely studied using the FISH test to identify standard and high-risk disease. This may help guide treatment. More genetic tests are being developed, usually in ongoing research studies.

  • Minimal residual disease (MRD). As treatments have become increasingly effective in treating myeloma, new approaches to measure how well a treatment works have been developed, including MRD. The principle is that the harder it is to detect the disease, the better. If disease is found (called "MRD positive"), further treatment may be offered to suppress the disease further.

After diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the cancer. This is called staging.

The next section in this guide is Stages. It explains the system doctors use to describe the extent of the disease. Use the menu to choose another section to read in this guide.