[Use of a new rheometer for the study of the filtrability of a suspension of sickled red cells as a function of PO2].

The filtration time of a small volume (0.1 ml) of red cell suspension from normal (AA), heterozygous (AS) and homozygous (SS) subjects for sickle cell disease was investigated as a function of PO2 The curve of filtration time of AS and SS red cell suspensions was biphasic. At high values of PO2, the progressive reduction of filtrability of sickle cell suspensions with decreasing PO2 occurred without new change in morphology of most of the cells. In contrast, at lower PO2 the apparent filtrability was improved and the cells were sickled." However the red blood cells were retained by the filter and the "solvent" filtrability was improved because rigid and highly deformed sickled cells did not clogged completely the pores of the filter. This study allowed to distinguish a new concept of apparent filtrability for red blood cells in sickle cell disease.