Multiple Myeloma: Diagnosis

Approved by the Cancer.Net Editorial Board, 07/2022

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 the cancer has spread, it is called metastasis. 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.

How multiple myeloma is diagnosed

There are different tests used for diagnosing multiple myeloma. Not all tests described here 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. Blood and urine tests play a key role in diagnosing myeloma.

  • M protein. Myeloma cells often secrete the monoclonal antibody immunoglobulin, known as M protein. M protein levels in a patient's blood and urine are used to determine the extent of the disease, as well as to monitor how well treatment is working and whether the disease is progressing or coming back. 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).

  • Immunoglobulin. 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.

  • Light chains. 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.

  • Serum albumin and serum beta-2 microglobulin (β2-M). The levels of serum albumin and serum β2-M are 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.

  • Lactase dehydrogenase (LDH). LDH is an enzyme, which is a type of protein. It is in almost all tissues in the body. Damaged tissues release LDH into the bloodstream, so LDH is used as a sign that the body has been injured or a disease is present. In myeloma, LDH levels can be used to help determine prognosis, which is the chance of recovery, and the stage (see Stages).

These test 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 creates 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. An x-ray skeletal survey may not find myeloma as early as the more advanced tests described below.

Magnetic resonance imaging (MRI). An MRI produces detailed images of the inside of the body using magnetic fields, not x-rays. 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 marrow 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 a 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 a way to create pictures of organs and tissues inside the body. 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 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. However, the amount of radiation in the substance is too low to be harmful. A scanner then detects this substance to produce images of the inside of the body.

Bone marrow aspiration and biopsy. These 2 procedures are done 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. These procedures are often done at the same time and may be called a bone marrow examination. 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 genetics of the malignant plasma cells are examined using cytogenetics (see below) and a special testing called fluorescence in situ hybridization (FISH). 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 local 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.

Biomarker 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. This may also be called molecular testing of the tumor. 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 genetics 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.

  • Fluorescence in situ hybridization (FISH). The FISH test is a type of cytogenetic test that uses a fluorescent dye to find changes in a person's chromosomes. FISH helps the doctor know whether the myeloma is high risk and aggressive, and it helps predict the prognosis. The FISH test will be used for most people with myeloma.

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

After diagnostic tests are done, your doctor will review the results with you. If the diagnosis is myeloma, 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 a different section to read in this guide.

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 a different section to read in this guide.