Influence of red blood cell concentration on the initiation time of blood coagulation: risk of thrombus formation by hemoconcentration.

Influence of the change of red blood cell (RBC) concentration on the initiation time of blood coagulation was investigated with a damped oscillation rheometer. The blood samples from 40 volunteers were examined. After centrifuging some portion of each blood sample, an appropriate volume was taken from the lower RBC layer to add it to the autologous blood, making an artificially concentrated blood. Initiation time of coagulation of each sample from 20 males and 20 non-pregnant females was shortened according to the increase of the RBC concentration, producing a significant difference at the boundary of 5.0x10(6)/mm3 (p<0.01). The results suggest that RBC concentration may play an important role in accelerating the initial coagulation reaction of blood and that hemoconcentration could be a risk factor for thrombosis even within the normal range, especially beyond the boundary of 5.0x10(6)/mm3 of RBCs.