Sedimentation of rbcs is impeded by other rbcs around it

why is ESR low in polycythemia rubra Vera?

Sedimentation of rbcs is impeded by other rbcs around it . So more the RBCs are in no. more is the impedance and more is the impedance less is the sedimentation rate .

So ESR is more in anemia and less in Polycythemia. Just imagine you want to reach station and you took taxi , more traffic you will take more time , less traffic you will take less time .

alright thanks!