A hemolytic anaemia is an anaemia resulting from an increased rate of red cell destruction. This results in a shortening of the red cell life span. Erythropoiesis in the bone marrow can expand by up to 6-fold to compensate for accelerated red cell destruction, but anaemia results when red cell destruction exceeds erythropoiesis. Increased erythropoiesis leads to a reticulocytosis. The clinical features of a haemolytic anaemia depend on whether haemolysis is acute or chronic.