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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 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 metastasized. Your doctor may consider these factors when choosing a diagnostic test:
- Age and medical condition
- Type of cancer suspected
- Severity of symptoms
- Previous test results
In addition to a physical examination, the following tests may be used to diagnose Waldenström’s macroglobulinemia:
Blood tests. Blood tests, such as CBC-D (complete blood count with differential count) and examination of the blood smears, can give clues to the diagnosis of Waldenström’s macroglobulinemia. There is also an increase in IgM that can be detected by protein electrophoresis (a method of separating proteins in the blood with an electric field).
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). The type of biopsy performed depends on the location of the cancer.
The most common type of biopsy for Waldenström’s macroglobulinemia is either a bone marrow biopsy (see below) or a biopsy of lymph nodes in the neck, under the arms, or in the groin. A biopsy may also be taken from the chest or abdomen under the guidance of a computed tomography (CT or CAT) scan (see below), or from the stomach or intestine during an endoscopy. An endoscopy is a test that allows the doctor to see inside the body using a thin, lighted, flexible tube called an endoscope.
Bone marrow aspiration and biopsy. Lymphoma often spreads to the bone marrow, the spongy material in the center of bones where blood cells are produced. A sampling of the bone marrow can be important in the diagnosis of Waldenström’s macroglobulinemia, and it can help determine if the cancer has spread.
A bone marrow aspiration and biopsy 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. An aspiration removes a sample of fluid with a needle. The sample(s) are then analyzed by a pathologist. 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 a local anesthetic beforehand (medication to block the awareness of pain), and other types of anesthesia may be used.
Molecular testing. Your doctor may recommend running laboratory tests on a tissue sample to identify specific genes, proteins, and other factors unique to the tumor. Results of these tests will help decide whether your treatment options include a type of treatment called targeted therapy (see Treatment).
CT or CAT scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities, tumors, enlarged lymph nodes, or a swollen spleen. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Magnetic resonance imaging (MRI) scan. An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium (a special dye) may be injected into a patient’s vein to create a clearer picture.
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 have higher metabolic activity (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.
Learn more about what to expect when having common tests, procedures, and scans.
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. Learn more about the first steps to take after a diagnosis of cancer.