A study of the haematological and haemorheological consequences of venesection.

A study has been made of a number of haematological and haemorheological factors following venesection therapy. Haematocrit was very effectively reduced by the venesection regimen and led to a fall in whole blood viscosity in spite of the microcytosis that was eventually induced in all the subjects. No clinically significant coagulation changes were observed. It is concluded that a simple venesection regimen without volume replacement is a safe procedure for improving blood rheology.