Multiple myeloma is diagnosed based on the results of clinical tests. To diagnose myeloma and related disorders, doctors use evidence from tests findings such as cancer cells in the bone marrow, kidney dysfunction, abnormal proteins in the blood, low levels of red blood cells, and imaging scans that show tumors.

When multiple myeloma is diagnosed, it is also assigned a stage. Knowing the stage provides clues as to which cancer treatment options may work best.

Diagnostic Criteria for Multiple Myeloma

Traditionally, people were diagnosed with myeloma only if they had signs of organ damage, such as:

• Hypercalcemia (high calcium levels in blood)
• Decreased kidney function
• Anemia (low red blood cell count)
• Bone lesions (tumors) visible on imaging tests

Now, doctors will also diagnose multiple myeloma if tests show that a person has one or more of the following signs of myeloma:

• 60 percent or more of the cells in the bone marrow as abnormal plasma cells
• High levels of abnormal light chains (proteins produced by abnormal plasma cells)
• More than one lesion visible in MRI studies
• Evidence of organ damage (high calcium levels, anemia, kidney failure, or bony lesions shown on imaging tests)

Additionally, doctors will see if a biopsy (removal of a small piece of tumor) shows that 10 percent or more of a person’s bone marrow cells are abnormal plasma cells.

Tests and What They Show

Primary care physicians are often the first to suspect multiple myeloma. Some people go to their doctor when they experience myeloma symptoms such as back pain, bone pain, frequent infections, or fatigue. In other cases, multiple myeloma is diagnosed after blood tests for an unrelated condition reveal abnormalities or after lesions show up in imaging tests for a broken bone. If your doctor suspects multiple myeloma, they will perform a number of tests to confirm the diagnosis and determine the extent of the cancer.

People suspected of having myeloma or a related disorder are often referred to an oncologist (cancer specialist), hematologist (specialist in blood cancers and blood disorders), or a doctor with combined specialties — a hematologist-oncologist. Another specialist called a hematopathologist examines blood and bone marrow samples in a laboratory to provide details necessary to diagnose and stage myeloma.

Medical History and Physical Examination

Your doctor will ask detailed questions about your medical history, including any inquiries about symptoms such as fatigue, bone pain, and frequent infections. They may ask whether anyone in your family has ever been diagnosed with myeloma or another type of blood cell disorder. The doctor may ask about your work or hobbies to find out if you may have been exposed to chemicals or radiation, which are risk factors for multiple myeloma. A physical exam will allow your doctor to check for signs of anemia, bone pain, weight loss, neuropathy (pain, numbness, or tingling in the extremities), or edema (swelling).

Blood and Urine Tests

Results from blood and urine tests are not diagnostic for multiple myeloma, but they can provide evidence that points to multiple myeloma or another condition. Some examples of what blood and urine tests could reveal include:

• Anemia — May show that cancer cells are destroying bone marrow
• High calcium level — Could indicate that bones are being damaged by tumors
• Elevated creatinine and urea nitrogen levels — Can indicate that the kidneys are not working well
• Low albumin levels — Can be a sign in some people with myeloma
• Elevated beta-2 microglobulin levels — May indicate immune system activation, or act as a tumor marker
• Increased lactate dehydrogenase (LDH) levels — Could point to tissue damage caused by cancer or another condition
• High C-reactive protein (CRP) levels — Can indicate inflammation in the body

Both blood and urine tests can show whether the body is making abnormal antibodies called M proteins, monoclonal proteins, or Bence-Jones proteins. The presence of M proteins is a sign that something is wrong with the plasma cells. Tests to measure and define M protein levels include:

• Serum protein electrophoresis
• Urine protein electrophoresis
• Immunofixation electrophoresis of urine or blood
• Quantitative immunoglobulin testing
• Serum free light chain assay

Some of these blood and urine tests also help analyze kidney function. People with myeloma often experience kidney damage due to M proteins or high calcium levels.

Learn more about lab tests for multiple myeloma.

Bone Marrow Aspiration and Biopsy

If blood and urine test results show strong indicators of multiple myeloma, your doctor will likely order a bone marrow aspiration and biopsy to confirm the diagnosis. These two procedures are often performed at the same time. Bone marrow aspiration is the collection of liquid from bone marrow, while a bone marrow biopsy takes a sample of solid bone marrow. Both the aspiration and biopsy are performed by pushing a needle into a bone, usually the rear portion of the pelvis (hip bone). The doctor will numb the area before performing the aspiration and biopsy to reduce discomfort.

Biopsied bone marrow tissue will be analyzed in a laboratory to assess how many abnormal plasma cells are present in the bone marrow. Cytogenetic studies are used to examine the genes and chromosomes of the cells. Knowing the genetic changes present in myeloma cells helps doctors estimate prognosis.

Imaging Tests

Imaging studies are used to determine whether there are lesions or damage in the bones or soft tissues. X-rays, MRI scans, CT scans, and positron emission tomography (PET) scans may be performed to help determine how far multiple myeloma has spread.

Imaging tests are also used to create a skeletal survey. During a skeletal survey, doctors take images of all the bones in the body to look for any abnormalities.

Condition Guide

• Multiple Myeloma — An Overview
• Symptoms of Multiple Myeloma
• Multiple Myeloma Types and Related Conditions
• Stages of Multiple Myeloma
• Treatments for Multiple Myeloma
• What Causes Multiple Myeloma?

• Comorbidities and Complications of Multiple Myeloma