process of Hb being released by intravascular haemolysis

Last reviewed 08/2021

  • initially haemoglobin (Hb) forms complexes with haptoglobin and these are taken up by the reticulo-endothelial system
  • once stores of haptoglobin are used up then the Hb is degraded to haem in the circulation and binds to haemopexin
  • once stores of haemopexin are saturated then the haem binds to albumin to form methaemalbumin
  • in severe haemolysis then the free Hb is filtered by the kidneys and appears in the urine as haemosiderin
  • in massive haemolysis there is free haemoglobin in the urine