I have PV and was getting phlebotomies at least once, sometimes twice a month even though I was also taking hydroxy. but then I found a secret of keeping my counts low....I drink as much liquid as possible before the blood test and the drink that works best is Tonic. Yes, quinine thins your blood. I prefer Fever Tree because it does not contain preservatives. Is this cheating? It was recommended by the phlebotomist.