Affiliations: Cattedra di Patologia Medica IV, University of Florence, Policlinico di Careggi, 50134 Florence, Italy
Note: [] Accepted by: Editor H. Schmid-Schönbein
Abstract: The smallest amount of stiff red cells which impairs the filterability of a whole blood sample is unknown. In order to answer such a question, an investigation was carried out on whole blood and red cell suspensions in plasma (Hct 0.10). A different amount of stiff red cells was added to these samples. The cells were rigidified by keeping the blood in thermostat at 37°C for 24–32 hours. The amount of incubated blood added to native blood and erythrocyte suspension was 10%, 5%, and 2.5%, respectively. Blood viscosity, hematological parameters and erythrocyte filtration were influenced by different amounts of stiffened red cells. When a blood sample containing 2.5 rigid cells per hundred was compared to a native blood sample, all hemorheological tests were unchanged except for erythrocyte filtration. This showed a significant delay in filtration times and a significant change of CFI. The filtering procedure appears to be the most sensitive test to reveal the presence of some stiff erythrocytes, but it is unable to show whether the delay in filtration rate is determined by a reduction of the flexibility of few, many, or all red cells in a blood sample.
