ON THIS PAGE: You will find a list of the common tests, procedures, and scans that doctors can use to find out what’s wrong and identify the cause of the problem. To see other pages in this guide, use the colored boxes on the right side of your screen, or click “Next” at the bottom.
Doctors use many tests to diagnose cancer and find out if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy (the removal of a small amount of tissue for examination under a microscope) is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has spread. This list describes options for diagnosing this type of cancer, and not all tests listed will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:
- Age and medical condition
- Type of cancer suspected
- Signs and symptoms
- Previous test results
The following tests may be used to diagnose multiple myeloma:
Blood and urine tests. Myeloma cells often secrete an antibody known as the M protein (monoclonal immunoglobulin). Levels of the M protein 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 patients, the myeloma cells only secrete part of the antibody, which is called light chain.
The levels of serum albumin (a blood protein made by the liver that is necessary for maintaining proper blood volume) and serum beta 2-microglobulin (β2-M, a small protein that plays a role in immunologic defense) are measured using blood tests; these results are important for determining the stage  of the cancer. Blood tests are also used to measure kidney function, calcium levels, and blood counts  (for possible anemia).
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 are typically the first step in evaluating bones when myeloma is suspected or diagnosed.
Magnetic resonance imaging (MRI) . An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. An MRI can show replacement of normal bone marrow by myeloma cells or plasmacytoma (a plasma cell tumor growing in bone or soft tissue), especially in the skull, spine, and pelvis. The detailed images may also show compression fractures of the spine or a tumor pressing on nerve roots. A contrast medium (a special dye) may be injected into a patient’s vein or given orally (by mouth) to create a clearer picture.
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 images into a three-dimensional picture of the inside of the body. Sometimes, a contrast medium is injected into a patient’s vein or given orally to provide better detail, but it is used cautiously in patients with multiple myeloma because of a risk of kidney failure.
Positron emission tomography (PET) scan . A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body. This substance is absorbed mainly by organs and tissues that produce 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.
Integrated PET-CT scan . An integrated PET-CT scan combines the images from a positron emission tomography (PET) scan and a computed tomography (CT) scan, performed at the same time on the same machine. Together, the two scans create a more complete image than either test can offer alone.
Bone marrow biopsy and aspiration . These two procedures are similar and often done at the same time. Bone marrow has both a solid and a liquid part. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle, and it is important to making a diagnosis of myeloma. An aspiration removes a sample of fluid with a needle. The sample(s) are then analyzed by a pathologist, a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. A common site for a bone marrow biopsy and aspiration is the pelvic bone, which is located in the lower back by the hip. The skin in that area is numbed with medication beforehand, and other types of anesthesia (medication to block the awareness of pain) may be used.
Fat pad aspirate. If M proteins are deposited in body tissues, it can cause organ dysfunction. This condition is called amyloidosis . If amyloidosis is a consideration, it may be necessary to take a sample of the abdominal fat pad (the collection of fat around a person's abdomen) for examination under a microscope, called a biopsy .
Molecular testing of the tumor. Your doctor may recommend running laboratory tests on a tumor sample to identify specific genes, proteins, and other factors unique to the tumor. Results of these tests may help guide your treatment options (see the Treatment Options  section more details).
After these 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.
Choose “Next” (below, right) to continue reading this guide to learn about the different stages for this type of cancer. Or, use the colored boxes located on the right side of your screen to visit any section.