title: Whole blood viscosity in plasma cell dyscrasias.
abstract: OBJECTIVE
  Plasma or serum hyperviscosity in plasma cell dyscrasias (PCD) has been described as a risk factor for circulatory disturbances. Whole blood viscosity (WBV) would theoretically be a better biomarker but has not been studied in PCD.
  
  
  METHODS
  Plasma viscosity (PV) and WBV were measured in 89 subjects with PCD and in 60 healthy blood donors by free oscillation rheometry. A complete blood count was obtained using an automated hematology analyzer. Plasma proteins were quantitated by immunoturbidimetry.
  
  
  RESULTS
  The reference intervals for men & women were 1.16-1.36 & 1.16-1.38 mPa for PV, and 4.9-6.3 & 4.4-6.2 mPa for WBV, respectively. Of the PCD patients, 71% had PV above the reference limit and 40% were above the WBV limit. Multivariate analysis showed that WBV was independently related to hematocrit, PV, concentration of the monoclonal protein (M-protein), plasma fibrinogen concentration and albumin concentration. This model accounted for 76% of the variance in WBV. When the same model was applied to PV, only the concentration of the M-protein was significantly related and the model accounted only for 20% of the variance in PV.
  
  
  CONCLUSIONS
  PV cannot be used as a surrogate marker for WBV in PCD patients. Whole blood viscosity should replace plasma viscosity in patients with PCD.
authors.affiliation: School of Health and Medical Sciences, Örebro University, Örebro, Sweden. Electronic address: bertil.uggla@orebroll.se.
authors.forename: Bertil
authors.initials: B
authors.lastname: Uggla
authors.affiliation: Department of Medical Biosciences/Clinical Chemistry, Umeå University, Umeå, Sweden.
authors.forename: Torbjörn K
authors.initials: TK
authors.lastname: Nilsson
mesh_terms: D000368:Aged; D001782:Blood Donors; D001809:Blood Viscosity; D015331:Cohort Studies; D004911:Erythrocyte Volume; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006400:Hematocrit; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D015999:Multivariate Analysis; D010265:Paraproteinemias / Q000097:blood*; D010949:Plasma / Q000378:metabolism; D012016:Reference Values
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005340:Fibrinogen
keywords: M-protein; MGUS; Myeloma; Plasma viscosity; Whole blood viscosity