Improving accuracy of co-axial viscometry

Area of Science:

• Biomedical Engineering
• Hematology
• Rheology

Background:

• Red blood cell aggregation and sedimentation in viscometers hinder reproducible measurements at low shear rates.
• Accurate assessment of blood viscoelasticity and red cell aggregation dynamics is crucial for clinical diagnostics and therapeutic monitoring.

Purpose of the Study:

• To introduce a simple, effective method for achieving reproducible torque-time curves in blood viscosity measurements using a Contraves LS30 viscometer.
• To enhance the quantitative description of blood viscoelasticity and enable dynamic analysis of red cell aggregation.

Main Methods:

• A novel bob agitation technique (up-and-down movement) is employed before initiating sample rotation.
• This method ensures disaggregation and prevents sedimentation of red blood cells within the viscometer.
• The technique is applicable to coaxial cylinder viscometers with manual bob lowering.

Main Results:

• Achieved highly reproducible torque-time curves (within 1-2% amplitude variation) even at very low shear rates.
• Demonstrated consistent results with time-dependent blood samples.
• Enabled more accurate comparative measurements between different blood samples and assessment of therapeutic interventions.

Conclusions:

• The described agitation method significantly improves the reproducibility of low shear rate blood viscosity measurements.
• This technique provides a reliable experimental basis for quantitative blood viscoelasticity analysis and dynamic red cell aggregation studies.
• The method enhances accuracy in comparing samples and evaluating treatment efficacy, applicable to standard coaxial cylinder viscometers.