What Blood Tests Are Used to Diagnose Multiple Myeloma?

In many cases, myeloma is discovered when blood tests, done as part of a routine physical examination or for some other reason, reveal anemia or a high calcium level, or a high level of protein (or, less commonly, a low level of protein). A urine test may show protein in the urine. It is important to do both a blood test and a urine test for proteins when testing for myeloma. Occasionally, a chest X-ray will identify significant osteoporosis in the vertebral (spine) bones, or even compression of a vertebral body. Such findings should prompt further testing to detect the underlying cause.

At some point in this testing process, the health care professional refers the person to a blood cancer specialist (hematologist-oncologist). Once the evaluation is completed and the presumptive diagnosis confirmed, the findings are usually presented to the patient in person and also to the patient's referring health care professional in writing.

Blood and Urine Tests

Complete blood cell (CBC) count: This test measures the hemoglobin (the amount of oxygen-carrying protein) as well as the numbers of different cells in the blood.
The most important measures in the CBC are as follows:

• Hemoglobin and hematocrit: Hemoglobin is the amount of oxygen-carrying protein in the blood. Hematocrit is the percentage of red blood cells in the blood. A low hemoglobin or hematocrit value indicates anemia.
• White blood cell (WBC) count: This is a measure of how many white blood cells there are in a certain volume of blood.
• Platelet count: Platelets are an important part of the clot that forms when a blood vessel is broken or torn. A low platelet count may indicate a tendency to bleed or bruise.

White blood cell differential: In addition to a CBC, most laboratories report a "white blood cell differential," often abbreviated "diff." This test, which may be performed either manually or with an automated counter, gives a breakdown by percentages of the different types of blood cells that make up the white blood cell count. The percentages should add up to be 100. Sub-classifying the white blood cells can help determine if there are deficiencies in a particular type of cell.

Blood chemistry panel: This set of tests gives a broad look at levels of various substances in the blood that may indicate the severity of myeloma and myeloma-related complications.

• Protein: Two types of protein are commonly measured in the blood: albumin and globulins. A high level of total protein in the blood may be a clue to the presence of myeloma; an abnormal high or rarely a low level of globulins is even more suggestive.
• Calcium: A high level of calcium suggests active reabsorption of bone and thus active myeloma.
• Lactate dehydrogenase (LDH): A high level of this enzyme may indicate active myeloma.
• Blood urea nitrogen (BUN) and creatinine: These are indicators of kidney function. Elevated levels, particularly of creatinine, represent kidney dysfunction or kidney failure.

Immunoglobulin levels: Measuring levels of the immunoglobulins is one way of tracking the extent and progression of the disease. If the myeloma actively secretes one form of immunoglobulin, then the levels of the other normal immunoglobulins will be suppressed. For example, if a patient has IgG myeloma, the IgG level will be high, and the IgA and IgM levels will be low.

Serum protein electrophoresis (SPEP): This test measures the levels of various proteins in the blood. It is the best test for detecting and measuring the abnormal monoclonal protein level associated with myeloma.

Urine protein electrophoresis (UEP): This test measures the levels of various proteins in the urine. In light-chain-only disease, the abnormal proteins are usually detectable only in urine, not in blood.

Immunofixation (or immunoelectrophoresis, IEP): This test can reveal the specific type of abnormal protein produced by the myeloma.

A 24-hour urine test for Bence-Jones or light-chain proteins in the urine: This test measures the actual amount of myeloma protein being filtered out and put into urine by the kidneys.

Serum free light chain measurement: This test measures the amount of light chain, a type of myeloma protein, in the blood.

All of these tests help diagnose multiple myeloma from other cancers like non-Hodgkin lymphoma that does not produce these protein products.

Prognostic indicators: Various blood tests are used to predict the outcome (prognosis) for an individual. Some of these are simple tests done in every laboratory; others are done only in specialized labs or in research settings. Many of these are not yet used widely but may be in the future. Depending on the situation, these tests may or may not be performed.

• Beta2-microglobulin (B2M): A high level of this normal protein indicates extensive disease and a thus a poorer prognosis.
• C-reactive protein (CRP): A high level of this inflammatory marker may indicate a poor prognosis.
• Lactate dehydrogenase (LDH): A high level of this normal enzyme indicates extensive myeloma.
• In cases of IgM disease or WM, a serum viscosity test may be performed.