1st order laboratory parameters – obligatory laboratory tests.
- Small blood count [plasmocytoma/multiple myeloma: normochromic anemia (anemia), leukopenia (decreased white blood cell count), and thrombocytopenia (decreased platelet count); final may be pancytopenia (synonym: tricytopenia: decrease in all three cell series in the blood; stem cell disease)]
- Differential blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate) [plasmacytoma/multiple myeloma: ↑↑↑]
- Calcium [plasmocytoma/multiple myeloma: ↑]
- Urine status (rapid test for: pH, leukocytes, nitrite, protein, blood), sediment, urine culture (pathogen detection and resistogram) if necessary.
- Renal parameters – urea, creatinine, cystatin C or creatinine clearance if necessary [increase in renal retention parameters].
- Total protein in blood serum
- Serum electrophoresis / M-gradient
- Immunofixation electrophoresis
- Quantitative immunoglobulin determination (IgA, IgD, IgE, IgG, IgM).
- Quantitative kappa-lambda light chain determination.
- Uric acid
Laboratory parameters 2nd order – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Differentiation of proteins in the urine
- Bence-Jones proteins in urine [detection in plasmacytoma/multiple myeloma].
- Beta-2-microglobulin (β2-microglobulin) [high levels tend to be prognostically unfavorable]
- LDH
- Bone marrow aspiration with histological workup [proportion of more than 10% plasma cells is considered an unfavorable prognostic factor].
Diagnostic criteria for the differential diagnosis of symptomatic multiple myeloma (MM) from “smouldering (asymptomatic) MM” and monoclonal gammopathy of uncertain significance (MGUS):
MGUS* | Smouldering MM | Symptomatic MM (requiring treatment) | |
Monoclonal protein | <30 g/l in serum | ≥ 30 g/l in serum, small amounts (< 1 g/24h) possible in urine | Present in serum and/or urine |
and /or | |||
Percentage of plasma monoclonal cells in the bone marrow. | < 10 % | ≥ 10 % | > 10 % or plasmocytoma and |
Organ damage according to CRAB criteria (see below). | None | none | Organ damage present |
* An MGUS (see below) progresses to a plasmacytoma in approximately 1% of cases.
Myeloma disease requires treatment if at least one of the CRAB criteria is met. The acronym CRAB stands for:
- C = serum calcium concentration > 10.5 mg/dl.
- R = renal insufficiency (process leading to a slowly progressive reduction in renal function) (creatinine > 2 mg/dl).
- A = Anemia (hemoglobin concentration < 10 g/dl or 2 g/dl below normal).
- B = Osteopathy (osteolysis (bone loss) and/or osteoporosis (bone loss)).
Further notes
- Monoclonal gammopathy of uncertain significance (MGUS) – precancerous condition for lymphoproliferative disorders such as multiple myeloma or Waldenström’s disease; paraproteinemia with monoclonal IgM globulins without histologic infiltration of the bone marrow with plasma cells or lymphoma cells (i.e., there is no plasmacytoma/multiple myeloma or Waldenström’s disease); in the United States, monoclonal gammopathy of unclear significance (MGUS) is found in 3.2% of those over 50 years of age and 5.3% of those over 70 years of age; progresses to lymphoproliferative disease in 1.5% of cases per yearNote: MGUS may persist for more than 30 years before clinical disease develops; in these patients, an additional jag, the “M gradient,” can be seen in the gamma globulin region. This indicates the spread of cell clones in the bone marrow.