Mr. Hardeman et al., LASER-ASSISTED OPTICAL ROTATIONAL CELL ANALYZER (LORCA) .2. RED-BLOOD-CELL DEFORMABILITY - ELONGATION INDEX VERSUS CELL TRANSIT-TIME, Clinical hemorheology, 14(4), 1994, pp. 619-630
Red blood cell deformability was measured under normal and experimenta
l conditions with the Laser-assisted Optical Rotational Cell Analyser
(LORCA). Results were compared to simultaneously performed filtration
measurements using the Cell Transit Analyser (CTA). The deformability
parameters of the two methods were Elongation Index (EI) and mean Cell
Transit Time (CTT, respectively. Aside from instrumental and intra-in
dividual reproducibility, normal values, the effect of sample aging an
d of changing medium osmolality are reported. Furthermore, the respect
ive sensitivities were determined using red blood cells with slightly
impaired deformability. Both heat treatment and incubation in the pres
ence of low concentrations of glutaraldehyde are used to manipulate th
e deformability of the entire red cell population. It is concluded tha
t minor defects in red blood cell deformability are detected more easi
ly by the laser technique than by filtration. Even when the absolute d
ifferences in EI are small, they can be significant due to the very hi
gh reproducibility of the ektacytometric technique. Differentiation be
tween a decreased deformability of the entire RBC population and the p
resence of a small (i.e., 5% or higher) subpopulation of rigid cells c
an be achieved with the LORCA by combining the measured EI-values with
visual inspection of the diffraction pattern. Finally, no significant
correlation was found between the results of both techniques applied
to blood from 525 patients with various diseases.