Whole Blood Viscosity
Overview
Whole blood viscosity measures the resistance to flow of whole blood through vessels, determined primarily by hematocrit, plasma viscosity, red cell deformability, and aggregation. It reflects rheological properties influencing microvascular perfusion and cardiovascular hemodynamics. Elevated levels indicate hyperviscosity syndrome from polycythemia, multiple myeloma, or Waldenström macroglobulinemia, while low levels lack clinical significance; clinically useful for diagnosing hyperviscosity syndromes, guiding plasmapheresis, and risk stratification in hematologic malignancies though not routine due to specialized testing requirements.[openbiomarkerjournal]
Clinical Use Cases
- Diagnosing hyperviscosity syndrome in multiple myeloma.
- Monitoring Waldenström macroglobulinemia treatment response.
- Evaluating polycythemia vera microvascular symptoms.
- Assessing risk before monoclonal antibody therapy.
- Research cardiovascular risk assessment.
Specimen Types
- Whole blood (citrated).
- Native blood (non-anticoagulated).
Measurement Methods
- Capillary viscometry (Wells-Brookfield).
- Rotational viscometry.
- Microchannel flow systems.
Test Preparation and Influencing Factors
- Temperature controlled at 37°C measurement.
- Hematocrit primary determinant (>55% markedly elevates).
- Dehydration, cold agglutinins increase viscosity.
- Collect at standardized shear rates (native/shear-thinning).
- Avoid prolonged tourniquet application.
Synonyms
- WBV.
- Blood rheology.