L’aggiornamento dei criteri per la diagnosi di mieloma multiplo da parte dell’“International Myeloma Working Group”
1Laboratorio Generale, Dipartimento Aziendale Integrato dei Servizi, Azienda Ospedaliero-Universitaria Careggi, Firenze
2Azienda Ospedaliera Universitaria Integrata di Verona
The update of the criteria for the diagnosis of multiple myeloma by the International Myeloma Working Group (IMWG)
he IMWG has recently updated the disease definition of multiple myeloma, by adding validated biomarkers to the existing requirements of organ damage (hypercalcemia, renal insufficiency, anemia, bone lesions). These changes are based on the identification of biomarkers able to detect the subset of patients with smouldering multiple myeloma at imminent risk of developing organ damage and should, therefore, be considered for therapy. Considering that the clinical laboratory is involved in the measurement of these new markers, this paper is aimed to illustrate the proposed changes giving at the same time some indications for their accurate measurements. As for the organ damage, the major change is related to the evaluation of renal function: the new criteria include the estimation of the glomerular filtration rate using established formulas (eGFR) rather than the use of serum creatinine concentrations alone, as previously indicated. The diagnosis of renal insufficiency requires an eGFR <40 mL/min/1.73 m2. The criteria for anemia and hypercalcemia remain unchanged. As biomarker of malignancy, a ratio >100 of involved to uninvolved serum free light chains is recognized. Another relevant modification is the elimination of the monoclonal protein quantification; it is based on the consideration that an important percentage of patients with multiple myeloma does not show a serum or urine monoclonal protein. Other changes based on imaging techniques or bone marrow examination do not involve the clinical laboratory and are not discussed in this paper. Additional biomarkers will probably be indentified in the near future, but they need to be validated by more independent studies.