How is myeloma diagnosed?

A number of tests will be performed to investigate symptoms of myeloma and confirm a diagnosis. Some of the more common tests are:

a physical examination
blood tests
urine tests
imaging scans to look for bone damage, which may include X-rays, a computed tomography (CT) scan or magnetic resonance imaging (MRI)
bone marrow aspiration, where a thin needle is used to remove a sample of fluid (aspirate) from the bone marrow for examination under a microscope
trephine (or bone marrow) biopsy, where a needle is used to remove a small piece of bone and a sample of bone marrow for examination under a microscope
cytogenic tests, which look for changes in the chromosomes of plasma cells; the bone marrow sample taken during the biopsy is used for cytogenetic testing.

Staging^[8]

If you are diagnosed with myeloma, you might have more tests to determine the stage of the disease and whether the cancer has spread to other parts of the body. Knowing the stage of the disease helps your medical team plan the best treatment for you.

To work out how much the cancer has spread, you might have X-rays, MRI and bone density tests. You will also have blood tests, which help your doctor stage the disease. These tests check:

levels of beta-2 microglobulin, a protein produced by myeloma cells
levels of albumin, a protein produced by the liver
levels of lactate dehydrogenase (LDH), an enzyme released into the blood when cells are damaged or destroyed

The most commonly used staging system for myeloma is the Revised International Staging System, or R-ISS. The stages of myeloma are:^[10]

Stage I: beta-2-microglobulin level is below 3.5 mg/L and albumin level is 3.5 g/decilitre (dL) or higher
Stage II: blood levels are in between stage I and stage III.
Stage III: beta-2-microglobulin is 5.5 mg/L or higher, and LDH levels are high or there are certain changes in the chromosomes.

The SLiM criteria were added as part of the R-ISS. It has 3 specific signs, or biomarkers, that doctors look for when diagnosing myeloma. These are:

Significant plasmacytosis (more than 60% of abnormal plasma cells in the bone marrow)
Light chain ratio (a high level of free light chains, which are a form of paraprotein, in the blood)
MRI lesions (more than one area of abnormal bone that is 5 mm or more in size, found by MRI).

Doctors also use the CRAB criteria of myeloma-defining events to help identify people with myeloma who need to start treatment. These criteria include: