This is the second of four installments in a series covering investigative tools used for diagnosing multiple myeloma.

The diagnostic work-up for detecting multiple myeloma traditionally includes: (1) confirmation of excessive growth of plasma cells ^[1]; (2) evaluation of end-organ damage, which will be discussed here; and (3) determination of possible factors that may affect therapy and long-term outcome ^[2].

End-organ damage is damage to major body organs that are nourished by the blood, such as the kidneys. Characteristics that can indicate end-organ damage are anemia, hypercalcemia, renal dysfunction, and bone lesions.

Anemias as well as hypercalcemia are detectable with routine blood tests.

Renal dysfunction necessitates a renal biopsy if its association with myeloma is in question, for instance if a patient has a history of diabetes and hypertension and presents with monoclonal gammopathy of undetermined significance (MGUS). In such cases, the physician will attempt to determine whether the renal involvement is due to monoclonal protein (M-protein), the protein that causes myeloma.

Bone lesions are typically detected by a skeletal survey. However, a more sensitive technique called magnetic resonance imaging (MRI) can detect both bone lesions and bone marrow involvement due to myeloma. MRI is often used if a questionable lesion is observed and needs confirmation.

End-organ damage can also be associated with the following symptoms:

• Hyperviscosity of the blood, which can be confirmed by serum viscosity measurement;
• Amyloidosis, an abnormal accumulation of amyloid protein in organs that can be detected by tissue biopsy; and
• A history of recurrent bacterial infections.

For more information about diagnostic criteria for multiple myeloma, see the full article in the American Society of Hematology’s 2008 Education Program Book, Hematology ^[3].