The Irreversibly Sickled Cell; a Determinant of Haemolysis in Sickle Cell Anaemia

S ummary . Red cell survival was estimated in a group of adult sickle cell anaemia patients using the 51 Cr technique. Counts of irreversibly sickled cells were performed on thin coverslip preparations of capillary blood. These counts are relatively constant within the same individual but show marked variations between individuals. A significant correlation has been demonstrated between the irreversibly sickled cell count and the red cell survival. This correlation does not apply to sickle cell anaemia patients with splenomegaly in whom the irreversibly sickled cell count is always low.