Does iron deficiency in treated polycythemia vera affect whole blood viscosity?

The relation between whole blood viscosity and iron status was studied in 11 patients with polycythemia vera (PV) who were treated with venesection without iron supplementation. Six were already iron deficient at the start of the study, five were followed from normal iron status to deficiency. Iron status was investigated with serum ferritin, erythrocyte protoporphyrin, mean cell volume and mean cell hemoglobin. There was no correlation between whole blood viscosity at a fixed erythrocyte volume fraction of 44% and any of these variables. The mean whole blood viscosity during iron deficiency and during normal iron state did not differ. Even after several months of iron deficiency there was no increase in whole blood viscosity. It is concluded that iron deficiency in treated PV does not give increased whole blood viscosity.