If symptoms suggest that a person may have multiple myeloma, laboratory tests on the blood and/or urine, x-rays of the bones, and a bone marrow biopsy are usually done.

Laboratory Tests of Blood and Urine

The blood and/or urine can be examined for an abnormal immunoglobulin (or antibody) that may build up to high levels in the blood. Often, parts of this protein are excreted by the kidneys into the urine.

Finding the abnormal immunoglobulin in the blood and/or urine can help determine whether a plasma cell tumor is present. These abnormal proteins have several names, including monoclonal immunoglobulin, M protein, M spike, and paraprotein. The procedures used for finding a monoclonal immunoglobulin are laboratory techniques known as serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP). The presence of high levels of another protein, beta-2-microglobulin, may also indicate that myeloma is present, although this protein is elevated in the blood in other diseases of immune cells such as lymphoma.

Bone Marrow Biopsy

A bone marrow biopsy and aspiration (removing a sample of the inside of the bone with a needle) can be done to confirm a diagnosis of multiple myeloma. A doctor will use a microscope to look at the bone marrow tissue to determine if there are myeloma cells in the bone marrow and, if so, how many.

In this procedure, the back of the pelvic bone is numbed with local anesthetic. Then a biopsy needle is placed into the bone and used to remove a cylindrical piece of solid bone and some marrow that is about 1-inch long and 1/16-inch in diameter. After this some bone marrow is sucked up into a syringe. The aspirate (material removed by suction) contains a few drops of fluid and tiny fragments of marrow. If there is a single tumor (plasmacytoma), a biopsy may be taken there.

Imaging Studies

Bone X-rays

Bone destruction caused by the myeloma cells and the effects of bone-absorbing hormones they release can be detected with x-rays. A more detailed imaging study, called an MRI scan (see below), may locate bone destruction caused by the tumor before it is seen by x-ray examination.

Computed tomography (CT): The CT scan (also known as a CAT scan) is an x-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, as does a conventional x-ray, a CT scanner takes many pictures of the part of your body being studied as it rotates around you. A computer then combines these pictures into an image of a slice of your body. Sometimes, this test can help tell if your bones have been damaged by the myeloma.

Often after the first set of pictures is taken you will receive an intravenous injection of a radiocontrast agent, or dye. This helps better outline structures in your body. A second set of pictures is then taken. The injection can cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives, or rarely, more serious reactions like trouble breathing and low blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays. If you are receiving contrast material, it is important you tell the people injecting the material that you are diagnosed with myeloma. Some of these contrast agents can damage the kidneys of people with myeloma.

CT scans are more tedious than regular x-rays because they take longer and you usually need to lie still on a table for 15 to 30 minutes while they are being done. But just like other computerized devices, they are getting faster and your stay might be pleasantly short. Also, you might feel a bit confined by the equipment you lie within when the pictures are being taken.

CT scans can also be used to guide a biopsy needle precisely into a suspected bone tumor. For this procedure, called a CT-guided needle biopsy, the patient remains on the CT scanning table while a radiologist advances a biopsy needle toward the location of the tumor. CT scans are repeated until the doctors are confident that the needle is within the mass. A fine needle biopsy sample (tiny fragment of tissue) or a core needle biopsy sample (a thin cylinder of tissue about ½-inch long and less than 1/8 inch in diameter) is removed and examined under a microscope.

Magnetic resonance imaging (MRI): MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. Not only does this produce cross-sectional slices of the body like a CT scanner, it can also produce slices that are parallel with the length of your body. A dye (contrast material) might be injected just as with CT scans but is used less often.

MRI scans are very helpful in looking at bones. MRI scans are a little more uncomfortable than CT scans. First, they take longer – often up to an hour. Also, you have to be placed inside tube-like equipment, which is confining and can upset people with claustrophobia. The machine also makes a thumping noise that you may find disturbing. Some places provide headphones with music to block this out. Recently, open MRI’s are less confining.

Interpretation of Test Results

Results of any single test are not enough to make a diagnosis of multiple myeloma. Diagnosis is based on a combination of factors, including the patient's description of symptoms, the doctor's physical examination of the patient, and the results of blood tests and x-rays. The diagnosis of multiple myeloma requires that a patient with symptoms have at least 1 major criterion or at least 3 minor criteria from the list below:

Major criteria:
A biopsy result shows a plasma cell tumor.
Over 30% of cells in the bone marrow sample are plasma cells.
The monoclonal immunoglobulin in the blood or urine exceeds a certain amount.

Minor criteria:
Between 10% and 30% of cells in the bone marrow sample are plasma cells.
A monoclonal immunoglobulin is found but not enough is present to fulfill a major criterion.
Holes in bones due to tumor growth are found on imaging studies.
The amount of normal antibody (not produced by the cancer cells) in the blood is abnormally low.

Source: American Cancer Society