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Hematocrit .36

Hi Guys, just wanted to ask if anyone else with PV has had hematocrit as low as .36. I had a pint taken off in November when I shouldn't have and at the latest blood test hct has gone down from .37 (after the venesection) to .36. My haemaglobin and ferritin are also low of course. Feeling pretty fatigued and a bit light headed sometimes but my GP says just to take things easy. Do I need to be speaking to my haem again? Kind regards Aime x

11 Replies

I not an expert but I have PV and I've been to see Claire Harrison at Guy's in London recently and she told me that .45 was the level I should be aiming at, anything above that then I should have a vensection. Yours sounds a bit low but I don't know weather that's specific to you or low in general.


45 for guys and 42 or was it 43 for women

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Lol should have pointed out I was a guy.



36 seems low , women should be under 42 so its likely the lower you go the more fatigued you will be, how did you have venisections you should not have had?. I always get tested a few days or a week before my venisection is due to see IF I need one. You can ask your haem or in my case if my Hct goes too low I take 5 to 10mg iron a day to get it up, be careful because its easy to overdo it on the way up, get checked every 3 weeks or so. Also keep an eye on your MCV this is the one to show how iron deficient you really are. Mine is around 60 which is low, if it goes to 57 know I am going to feel too rough so I add some iron. Just be careful not to overdo it. If you have good haem they can tell you all of the above.


Hello Aime

The big thing is to check your iron levels - not surprised you are a little light headed mind you with that low figure. Don't worry though, mine has been even lower on one occasion. However, because I am taking Ruxolitinib now which is inclined to reduce iron as well, I have just had a red cell transfusion which made me laugh thinking at how many venesections I have had over the past two years or so, to take them away!!!! What a funny world it is.

Don't waste time by worrying though as you have had enough to contend with altogether but do check with haem as they are the expert.

Take care,




.36 is bottom end normal for women. Whats your hgb and ferritin levels? Im guessing your HGB will be about 11-12?

You can have normal HGB/HCT and be low in ferritin which would certianly contribute to tirendess and dizzy spells.



Hi there Aime

36 does seem low, I always feel better after having a unit taken if my counts are high however, my doc's aim for 45 as the required mark, after a few hours of the venesection, I tend to hit the "wall" and need to rest and take things steady the day after before getting back to "normality".



Hi Guys, thank you all for your replies. The blood was taken off in error because the clinic nurse looked at the wrong blood test results!! After the venesection my hct was .37 and now it has gone down to .36. HGB is 11, not sure what ferritin is but GP said it was low. Not sure whether I should be asking for haem appointment or just soldier on and wait until it rises. I get blood taken off normally at .45 and have never been as low as .36. Maz - could you possibly ask Prof Harrison for advice please. Many thanks to all Aime xx



Sorry to be contrary but I wouldn t worry too much.

In the US I think a haematocrit of 36 to 42 is considered normal.

To be honest I think we're all different.

I feel at my best around 41/42 - get headaches and visual disturbances over 45.

I think the advice of taking it easy at a level of 36 is probably wise - al though it's bound to creep up again.




Hi, Long term MF patient in the US (24 years), who usually has a hct of 36, as low as 31 & back up to 40 at some times. However usually average in 35-37 range. As result have had mild anemia over the years with the fatigue. Have learned to adjust my life around it & emotionally deal with it.


A belated thank you for your answers guys. I have had daughter and family staying while their new house was being built and had a great time with my grandson but have been exhausted, going to bed the same time as him! I ended up with my heam putting me onto 2 weeks only of iron tabs which made a huge difference at a difficult time. My daughter and family now into their house so I can collapse onto sofa after work again. Take care, kindest regards


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