Question

A 53-year-old male patient with an established diagnosis of IgG ? multiple myeloma

was seen by a hematologist?oncologist in consultation from an outside hospital. He

had previously received 1 cycle of chemotherapy treatment, but he was found to be

Intermittently noncompliant with his therapy. The patient reported occasional

nosebleeds and fatigue. Except for a slightly cachectic appearance, the physical

examination was unremarkable. Laboratory results are shown in Table 1.

Serum protein electrophoresis revealed monoclonal paraproteinemia in high

abundance marked by an intense band in the   region. Immunofixation g

electrophoresis was not ordered at that time, but it was previously performed at

another institution and was positive for IgG monoclonal protein.

The attending pathologist noted the discrepancy between the presence of a

monoclonal band by serum protein electrophoresis and the patient?s quantitative

immunoglobulin measurements. Several additional suspicious test results were also noted:

1. What are some expected laboratory results in a patient with multiple myeloma?

2. Which of the patient?s laboratory test results are unexpected given his diagnosis of

multiple myeloma?

3. What types of laboratory errors can occur in patients with multiple myeloma?

Answer 1

Multiple myeloma is a cancer that forms in a type of white blood cell called a plasma cell. Plasma cells help you fight infections by making antibodies that recognize and attack germs. Multiple myeloma causes cancer cells to accumulate in the bone marrow, where they crowd out healthy blood cells.

1.(CBC) is a test that measures the levels of red cells, white cells, and platelets in the blood. If there are too many myeloma cells in the bone marrow, some of these blood cell levels can be low. The most common finding is a low red blood cell count (anemia).

Laboratory tests

• Elevated total protein
• Elevated calcium
• Low white or red blood cell count
• Moderate to large amounts of protein in the urine

2.

monoclonal paraproteinemia in high abundance marked by an intense band

3.

Multiple myeloma is a hematologic malignancy characterized by proliferation of a neoplastic plasma cell population that usually leads to abundant production of a monoclonal immunoglobulin, also called paraprotein or M-protein, as well as decreased concentrations of normal polyclonal immunoglobulin. Overproduction of plasma proteins in concentrations that exceed typical physiologic limits can be an important source of laboratory test interference.

For example, a paraprotein associated increase in blood viscosity can cause difficulty in sample aspiration by some instruments that results in assessments being performed on smaller-than-expected sample volumes and subsequent falsely decreased laboratory results.