Calculated whole blood viscosity and erythrocytes parameters in plasma cell dyscrasias: Insights from MGUS and SMM

BACKGROUND AND OBJECTIVE: In the plasma cell dyscrasias, monoclonal gammopathy of undetermined significance and smoldering multiple myeloma represent the asymptomatic form, but, in their clinical course we can observe some pathological conditions. For this reason, our aim is to evaluate calculated whole blood viscosity and some erythrocyte indices, to obtain information on mechanisms underlying thrombotic risk and microcirculatory alterations. PATIENTS AND METHODS: We retrospectively evaluated calculated whole blood viscosity (according to the de Simone formula), hematocrit, plasma protein concentration, RDW, hemoglobin, RDW/albumin and RDW/hemoglobin ratios in 50 subjects with MGUS [median age 64.00 (16.059)] and in 93 SMM patients [median age 69.00 (13.00)]. RESULTS: From the data comparison, obtained with the Mann-Whitney test, it emerges that the hematocrit value, is lower in patients with SMM unlike the plasma protein values which are higher in this nosographic entity. Serum albumin is significantly reduced in subjects with MGUS, while RDW and the RDW/albumin ratio are higher in these same subjects. No statistically significant results were obtained by subdividing each nosographic entity according to both isotype (IgA and IgG) and risk level. CONCLUSIONS: The evaluated erythrocyte indices could represent a simple and accessible parameters for a better clinical evaluation, and further risk stratification, warranting a next prospective validation.