PV & Venesections

Hi community,

I've was diagnosed with PV about 3 years ago and have gone through many tests including a couple of sessions at Guys hospital. All tests were inconclusive and although its difficult to prove diagnosis is for secondary PV although I have had many of the symptoms off and on since childhood.

Regardless of cause what I am interested in finding out is at what level does your hospital recommend you have venesection. I think the blood level is different in men to women so prefer feedback from women. The internet says "the normal hematocrit for men is 40 to 54%; for women it is 36 to 48%" but what I want to know if at what level does your consultant recommend venesection as treatment.


8 Replies

  • Hi, I was diagnosed 4 years ago when my haemaglobin was 171 g/L and am thought to have Secondary Polycythaemia - undetermined cause. I'm JAK2, EXON12 & CALR mutation negative and am treated by venesection only. The diagnosis could equally be PV - undetermined cause as no cause has been found. I am venesected as soon as my Packed Cell Volume (PCV), also called haematocrit, reaches 0.45. I have a Full Blood Count every 4 months and can go as much as 10 months between venesections but usually less. I suffer from some fatigue and silent migraines which may not be connected with the Polycythaemia but am generally well. I don't have any of the suspected secondary causes. I now have very low ferritin levels which slows down the red blood cell production. Hope this helps and you keep well. Jackie.

  • I am sure every consultant will differ, but when I have gone as low as 40 they wont venesection me. I usually have to be around 43-44. That is in Edinburgh but as I say every consultant will think differently. Hope that helps.


  • Hi Michele, I'm from Aberdeen, PV, JAK2+. At my clinic they work to a target of 0.45. I have a venesection any time my level is above that. Still fairly new to it though as I was only diagnosed in June this year. Hope this helps.

    Liz K

  • I'm currently on venesections only for PV JAK2+ & have to have them as soon as HCT goes over 45.

  • Hi Michelle,

    the range may be 39 to 45 but I find I can't go above 42. I have PV for 12 years and over that time realised if it went above 42 I got headaches and blurred vision so now my records show if test results are above 42 I have immediate venesection. And I feel so much better afterwards.

    I am on interferon and the dose and frequency is adjusted so I keep to about 40. That's suits me very well. I rarely need venesections now.

    So, I guess it depends on the individual. Some can tolerate higher HCT and some can't. Hope you find the best safe level for you.


  • Thanks. I'm being kept at about 5 because of low iron levels but start to feel it at 4.6 I can always tell its more or less exact every time. Further tests in progress so hope to have a another review soon. I empathise with the blurred vision but only seem to get headaches immediately after the venesection not before. Symptoms tend to vary but when I was first diagnosed I was very light headed, fainting and had what I thought was glandular fever for a couple of months. Now tend to get tingling in limbs, heavy feeling in calves and difficulty concentrating. Once venesection its more or less an immediate improvement and I feel normal again.

  • Hi Michelle. My specialist nurse works to keep mine under 45. I had venesections for five years then went on to Hydroxycarbomide. Hope this helps . L x

  • Thanks. There has been no mention of medications so far but I guess it will happen at some stage. :)

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