In severe extra-vascular hemolysis, haptoglobin levels can also be low, when large amount of hemoglobin in the reticuloendothelial system leads to transfer of free hemoglobin into plasma.
22.
While there they discovered techniques to study the clearance of particulate matter from the blood by the RES ( reticuloendothelial system ), and devised equations that govern this process in mammals.
23.
"Reticuloendothelial system " is an older term for the mononuclear phagocyte system, but it is used less commonly now, as it is understood that most endothelial cells are not macrophages.
24.
Conversely, in extravascular hemolysis the reticuloendothelial system, especially splenic monocytes, phagocytose the erythrocytes and hemoglobin is relatively not released into circulation; however, excess hemolysis can release some hemoglobin causing haptoglobin levels to be decreased.