Multiple Myeloma Diagnosis

Multiple myeloma is a malignant hematological tumor characterized by abnormal proliferation of plasma cells in the bone marrow. If not diagnosed early, it can rapidly destroy bone, impair the hematopoietic system, and cause renal failure. Clinical diagnosis usually requires comprehensive analysis combining laboratory tests, imaging, and bone marrow biopsy to exclude other diseases and confirm clonal plasma cell proliferation.

Diagnostic Basis

1. Serum protein electrophoresis and immunofixation electrophoresis
This is the most commonly used laboratory method for screening myeloma. By analyzing whether M protein (monoclonal immunoglobulin) is present in patient serum, plasma cell abnormalities can be preliminarily identified. Immunofixation further clarifies M protein type, such as IgG or IgA, aiding classification and follow-up.

2. Urine protein test (Bence-Jones protein)
Myeloma patients often show increased excretion of Bence-Jones protein (a type of light chain immunoglobulin). Detection through urine immunoelectrophoresis or immunofixation indicates tumor cell secretion activity and is important for assessing kidney damage.

3. Bone marrow puncture and biopsy
This is the core step for diagnosing multiple myeloma. Morphological observation and flow cytometry analysis of plasma cell proportion and clonality establish diagnostic evidence. Bone marrow plasma cells exceeding 10% is one of the key diagnostic criteria, while excluding other plasma cell proliferative diseases.

4. Blood tests and kidney function assessment
Patients often present with varying degrees of anemia, along with decreased white blood cells and platelets, suggesting bone marrow suppression. Elevated serum creatinine and urea nitrogen reflect kidney impairment, serving as important diagnostic indicators. In addition, serum calcium should be monitored to identify hypercalcemia risk.

5. Imaging examinations
Conventional X-ray or CT scans may reveal typical "punched-out" osteolytic lesions, often found in the skull, vertebrae, ribs, and pelvis. MRI is more sensitive in detecting the extent of bone marrow involvement, identifying infiltration before bone destruction occurs. PET-CT provides more precise assessment of disease activity.

6. Light chain assay and FLC ratio
Free light chain (FLC) testing can detect non-secretory or light-chain myeloma, particularly in clinically suspected but electrophoresis-negative patients. An abnormal κ/λ ratio often indicates clonal plasma cell origin, helping in early identification of occult myeloma.

7. Histopathology and immunomarker testing
When necessary, pathological staining and immunohistochemistry can confirm plasma cell type and exclude other hematological malignancies. Immunomarkers such as CD38 and CD138 help determine cell origin and guide targeted treatment strategies.

Conclusion

Experts at United Life International Medical Center remind us that diagnosis of multiple myeloma requires a combination of multiple tests. Early detection of M protein, bone marrow plasma cell proportion, and imaging changes is crucial for staging the disease and selecting treatment strategies.