Diagnosing Multiple Myeloma: Key Tests and Advanced Diagnostic Approaches
Multiple myeloma is a complex blood cancer that often develops silently, with subtle or nonspecific early symptoms. Because of this, accurate diagnosis relies heavily on a comprehensive series of clinical and laboratory evaluations. Early detection significantly improves treatment outcomes, making it essential to understand the range of diagnostic tools available.
Essential Laboratory Blood Tests
Biochemical profile testing plays a critical role in identifying abnormalities associated with multiple myeloma. A hallmark sign is the presence of elevated levels of abnormal serum proteins, particularly monoclonal (M) proteins, while albumin levels remain normal or decrease. Serum protein electrophoresis or specific M-protein assays typically reveal a distinctive sharp peak known as the "M spike," which strongly suggests plasma cell dyscrasia.
In addition, urine testing for Bence Jones protein—a type of light chain immunoglobulin excreted in the urine—is positive in approximately 50% of patients. This finding further supports the diagnosis and helps assess disease burden and kidney involvement.
Blood Count Analysis and Anemia Patterns
Complete blood count (CBC) results often show anemia, typically of the normocytic and normochromic type, meaning red blood cells are normal in size and color but reduced in number. This kind of anemia reflects bone marrow suppression caused by the infiltration of malignant plasma cells. Platelet counts may be normal or slightly decreased, while white blood cell levels can also be affected in advanced cases.
Confirmatory Bone Marrow Examination
The bone marrow biopsy remains a cornerstone in confirming multiple myeloma. A sample from the pelvic bone is analyzed to determine the percentage and appearance of plasma cells. According to diagnostic criteria, the presence of clonal plasma cells accounting for at least 10% of nucleated cells—especially if they appear immature or morphologically abnormal—is a key indicator of the disease.
This test not only confirms malignancy but also allows for additional genetic and molecular studies, such as fluorescence in situ hybridization (FISH), which can detect chromosomal abnormalities linked to prognosis and treatment planning.
Imaging Techniques for Bone Assessment
Skeletal radiography is traditionally used to identify bone damage caused by myeloma cells. Classic findings include multiple "punched-out" lytic lesions, osteoporosis, and pathological fractures—particularly in the skull, spine, pelvis, and ribs. These occur due to increased osteoclast activity triggered by tumor-secreted factors.
Advanced Imaging Options
While X-rays are useful, more sensitive imaging modalities like computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly preferred, especially for detecting early or subtle bone involvement. MRI is particularly effective in evaluating spinal cord compression or marrow infiltration in asymptomatic regions.
Positron emission tomography (PET-CT) scans are also being integrated into staging protocols, offering functional insights into active tumor sites and helping monitor response to therapy.
Genetic and Molecular Profiling
Modern diagnostics go beyond structural and cellular analysis. Cytogenetic testing, including FISH, identifies high-risk genetic markers such as deletions in chromosome 17 or translocations involving the immunoglobulin heavy chain gene. These findings help classify disease subtypes, predict aggressiveness, and guide personalized treatment strategies.
Together, these advanced techniques enable clinicians to move toward precision medicine, tailoring therapies based on individual patient profiles for improved survival and quality of life.