[Electric conductivity of erythrocyte sediments and red blood cell deformability]

To assess the deformability of erythrocytes several methods can be used. The latter investigate either the properties of single blood cell or the properties of a red cell suspension. The objective of the present study was to assess whether experimentally induced deterioration of the red cell deformability can be recorded by measurements of the electric conduction of red cell sediment.

In ten patients with disorders of the circulation 10 ml blood samples were taken, mixed with a solution of sodium citrate and centrifuged at 1250 g for 10 minutes. The separated blood cells were repeatedly centrifuged and rinsed. Red cell deformability was experimentally enhanced by incubation of erythrocytes in a Ringer-albumin solution. The change of deformability was detected by viscosimetry and assessment of the electric conduction of the red cell sediment, using a conductometer Radelkis 101 OK, the temperature of the sediment being 10 degrees C. The viscosity values of red cell suspensions with a haematocrit of 0.45 were assessed at six shear rates and they were in all instances higher after incubation of red cell suspensions, as compared with the viscosity of suspensions of fresh erythrocytes. The mean value of electric conduction of the sediment with a haematocrit of 0.45 before incubation was 0.132 mS and after 24 hours incubation 0.218 mS; the difference was statistically significant (p < 0.0005).

Deterioration of red cell deformability is associated with improved electric conduction of the red cell suspension of sediment. It is possible to use assessment of electric conduction of the red cell sediment to assess erythrocyte deformability. The method is simple and cheap, as compared with the viscosimetric method.