Viscosity

Specimen:

5 mL blood in EDTA.

Method:

Capillary viscometry. The resistance of plasma to flow deformation is tested and the result is expressed as a ratio in comparison to water.

Reference Interval:

1.6-1.9

Refer to laboratory.

Application:

If a hyperviscosity state is suspected, Full blood count, Erythrocyte sedimentation rate, Protein (globulin), Protein electrophoresis and Protein electrophoresis urine with Free light chains should identify clinically important disorders; plasma viscosity is only rarely useful.

Interpretation:

Increased plasma viscosity supports the clinical diagnosis of hyperviscosity syndrome.

Clinical hyperviscosity syndromes are usually only seen with plasma viscosity > 5.

Reference:

Bain et al. Dacie and Lewis Practical Haematology. 11th Ed. 2012.