(It will also be informative to directly perform an assay (Monoclonal gammopathy evaluation) to identify the M-protein.)Įxample 2: Patient B's reported whole blood viscosity is 58% her concurrent (actual) hematocrit is 58%. If an M-protein is responsible, the plasma viscosity, expressed in cP, will also be increased above the upper limit of normal. This is most likely will be protein- e.g. In this example, the whole blood is more viscous than would be expected- based on hematocrit - therefore element(s) in addition to RBC, contribute to the increased whole blood viscosity. Whole blood viscosity- expressed in equivalent hematocrit can be thought of as 'this whole blood is as viscous as the whole blood would be if its hematocrit were X'Įxample 1: Patient A's reported whole blood viscosity is 54% his concurrent (actual) hematocrit is 36%. (The conversion from cP to hematocrit equivalent is based on the mathematical relationship between these two units of measure). Whole blood viscosity measurements are converted from centipoise to 'equivalent hematocrit'. The torque necessary to overcome the viscous resistance of whole blood or plasma is measured in centipoise (cP). Samples are warmed to 37 degrees in order to recapitulate core body temperature. Whole Blood and Plasma Viscosity: InterpretationĪnticoagulated whole blood and plasma viscosity are measured using a Brookfield cone-plate (rotary) viscometer.

Usually, a given patient's symptoms will reproducibly appear at a given viscosity, although this will vary from patient to patient. Most patients do not become symptomatic until the plasma viscosity exceeds 4.0 cP. Test includes directly measured plasma viscosity and the derived whole blood viscosity.

Blood viscosity tests