Multiple Myeloma Blood Tests: Purpose, Procedure, and Results
A complete blood count, chemistry profile, immunoglobulin test, and light chain assay are among the important blood tests doctors use to help diagnose multiple myeloma.
Multiple myeloma is a type of cancer that affects the white blood cells that your bone marrow produces.
Doctors can help diagnose multiple myeloma using blood tests. These measure changes in the levels of blood cells or proteins that may mean you have cancerous cells in your bone marrow.
Read on to learn about the blood tests for multiple myeloma, including what their results mean and how doctors use them to aid diagnosis.
Complete blood count
A complete blood count (CBC) is a common blood test done to measure the levels of blood cells that are part of your immune system, such as:
- red blood cells, including oxygen-carrying hemoglobin and the percentage of red blood cells in your blood (hematocrit)
- white blood cells that can increase in number when you have cancer or an infection
- platelets that control blood clotting and can suggest illness when they change in levels
With multiple myeloma, your red blood cells and platelets might decrease as your bone marrow loses its ability to produce enough of these blood cells.
Your white blood cells might increase in early stages of multiple myeloma but also decrease as cancer affects your bone marrow.
Blood chemistry profile
With a blood chemistry profile, healthcare professionals use a blood sample to monitor levels of substances in your blood that multiple myeloma can affect, including:
- calcium, which can rise to very high levels when you have multiple myeloma
- albumin, which can lower drastically when you have aggressive forms of multiple myeloma
- creatinine, which can increase due to kidney complications related to multiple myeloma
Quantitative immunoglobulin test
A quantitative immunoglobulin test can measure the levels of antibodies in your blood that respond to the presence of cancerous cells and changes in what your bone marrow can produce.
With multiple myeloma, you’ll typically show higher levels of antibodies called immunoglobulins on your test results.
Kidney disease that develops from multiple myeloma can also cause lowered immunoglobulin levels. Doctors may need to use this test alongside other tests to confirm a diagnosis of multiple myeloma.
Electrophoresis
A serum protein electrophoresis (SPEP) and immunofixation test — sometimes just called an electrophoresis test — involves placing a blood sample on a piece of paper that’s given an electric shock.
This test can split up antibodies into visible bands that help a healthcare professional note which antibodies are present.
When you have multiple myeloma, a doctor may see a band of M proteins made by cancerous myeloma cells on the paper.
Serum-free light chain assay
A serum-free light chain (SFLC) assay can help diagnose light chain myeloma, a subtype of multiple myeloma.
Doctors often request this test when an electrophoresis test doesn’t show the presence of any M proteins.
For the SFLC assay test, a healthcare professional will draw a blood sample to test it for the presence of light chain antibodies in your blood. Light chains are a part of what makes up immunoglobulins and are also associated with your blood plasma.
High levels of light chains in your blood can suggest you have light chain myeloma.
Beta-2 microglobulin test
The beta-2 microglobulin (B2M) test is a tumor marker test that looks for the presence of B2M proteins in your blood.
High levels of B2M in your blood can mean you have multiple myeloma or other blood or bone marrow cancers, such as chronic lymphocytic leukemia (CLL) or lymphoma.
Doctors won’t use the results of a B2M test on its own to diagnose multiple myeloma on its own. But several B2M tests over time can help a doctor figure out how aggressive your cancer is or how well treatments are working.
Multiple myeloma symptoms
Symptoms of multiple myeloma can depend on what stage you’re in and what organs are affected. Some symptoms you might experience include:
- unexplained shortness of breath
- feeling very thirsty
- nausea
- throwing up
- stomach pain
- losing your appetite
- not peeing as much as usual
- swelling in your legs and feet
- feeling drowsy or fatigued
- confusion
- chest pain
- unexplained seizures
- loss of consciousness or coma
Frequently asked questions
What is the most important blood test for multiple myeloma?
A complete blood count (CBC) is the most important blood test for multiple myeloma. A CBC test can clearly show levels of immune cells that are directly related to multiple myeloma.
However, to confirm a diagnosis, doctors will often need to consider results from a serum-free light chain assay along with your symptoms and imaging.
Would myeloma show up in a routine blood test?
An increase in your red or white blood cells on a routine blood test can mean that you have an active infection or cancer. If a doctor notices an increase in these immune cells, they might order other diagnostic tests to look for other signs of infections or cancer.
These tests will help them to confirm a diagnosis or rule out conditions.
Are blood tests enough to diagnose multiple myeloma?
Blood tests are not usually enough to confirm a diagnosis of multiple myeloma. If your blood test results suggest you might have multiple myeloma, a doctor will also perform a biopsy to test a sample of your bone marrow for the presence of cancerous cells.
Imaging tests, such as a CT scan or MRI, can also help confirm a diagnosis of multiple myeloma with detailed images of the affected bones or organs.
Takeaway
Numerous blood tests can help diagnose multiple myeloma by showing increased or decreased levels of blood cells and proteins.
Contact a doctor if you’re concerned that you have multiple myeloma and want help confirming a diagnosis.
