In haemolytic uraemic syndrome there is evidence of intravascular haemolysis owing to microangiopathy with fragmentation of red cells (click here for picture), a low serum haptoglobin concentration and a marginally raised serum indirect bilirubin concentration. Patients with this syndrome differ from those with other causes of renal failure in their ability to mount a reticulocyte response. The platelet count is reduced by consumption in microthrombi. There is no association with autoimmune haemolytic anaemia.
http://emedicine.medscape.com/article/982025-overview