Lorrca MaxSis - Introduction Osmoscan; Introduction RBC-Elongation; Introduction RBC-Aggregation

Instrument description
Page 26 Lorrca Maxsis User Manual
Version 5.04 MRN-231-EN
3.3.4.2. Introduction Osmoscan
The Lorrca® MaxSis has an optional equipment with the possibility for automatic measurement of
Red Blood Cell (RBC) deformability (expressed as elongation index, EI) as a continuous function of
suspending medium osmolality. Both the shape and the position along the osmolality axis of
specific features of these, so called osmoscans provide information about the cell`s deformability
(at the chosen shear stress) as well as their intracellular viscosity and surface-volume ratio. For
characterization of each osmoscan 4 parameters are defined:
 Omin (the osmolality at the EI minimum found in the hypotonic region)
 EImax (the maximal EI of the total curve)
 Omax (the osmolality at EI-max)
 Ohyper (the osmolality in the hypertonic region corresponding to 50% of the EI-max).
Application of this approach to a variety of RBC disorders is in line with first generation
ektacytometers.
Osmoscans obtained after various experimental manipulations (heat treatment, exposure to shear
stress and glutaraldehyde) of normal RBC, demonstrating the expected effects.
3.3.4.3. Introduction RBC-elongation
RBC elongation program quantifies the stress dependent (Deformability curve) and time dependent
(Stability test) deformability of red blood cells, or a combination of both (Cell Membrane Stability
Test). The software instructs the operator when to insert the test suspension, shows the current
temperature during warming-up and performs fully automatic RBC deformability and stability
measurements.
3.3.4.4. Introduction RBC-aggregation
RBC-aggregation software is written for measuring the syllectogram and for measuring the
threshold shear rate at which RBC aggregation is just prevented. The software instructs the
operator when to insert the test suspension. The investigator is enabled to select a syllectogram-
fitting model containing one to three exponents. The uni-exponential model is interesting to study,
e.g., RBC-shape recovery in buffer solution. The conventional bi-exponential model describes the
aggregation process while the tri-exponential model includes both RBC-shape recovery and
aggregation. Unlike other models, the tri-exponential model describes the whole syllectogram,
including the upstroke.