MGUS Diagnostic Algorithm

Authored by Vincent Rajkumar, published on 2026-04-29 17:44:04.0

Monoclonal Gammopathy of Undetermined Significance (MGUS) is diagnosed via blood and urine tests that detect abnormal M-proteins, typically identified during routine checkups. It is defined by a serum M-protein level < 3 g/dL, < 10% plasma cells in the bone marrow, and an absence of end-organ damage (no bone lesions, anemia, or kidney failure).

  1. Potential New MGUS
    • No clinical concerns, and • Low Risk*, or • IgM M protein <1.5 gm/dl, or • Light Chain abnormality only with FLC ratio between 0.125-8.0
      • Provisional Diagnosis of MGUS Bone marrow biopsy and bone imaging can be deferred
    • All other patients
      • Bone marrow biopsy and bone imaging
        • No evidence of Myeloma or SMM
          • Diagnosis of MGUS confirmed
        • Evidence of Myeloma or SMM
          • Follow SMM / Myeloma algorithm
tosprivacyDiagnosis and Management of Monoclonal Gammopathy of Undetermined Significance: A Review