Why is the hct threshold for females 42/43 in USA but 45 in UK. I'm in UK and it troubles me......

[Looolooo]

I live in UK, have PV, and on interferon which is working well. My doc has always been happy with my count being 45 or under. Why in USA is the hit lower?

[LittleLuna]

I am in UK too and 45 target for female.

I also wonder why the big difference in levels?

[Looolooo in reply to LittleLuna]

Can anyone help with this query?

[hunter5582]

Actually the HCT target in the USA is not universally 42/43% for females. It depends on who you see. I expect it is the same in the UK.

The reason for the difference based on gender is that the standard reference range for HCT is different for men and women. The WHO diagnostic criteria for males/females is also different. Many MPN Specialists have adjusted the HCT targets based on the difference in male-female physiology, but not all.

In my view, what is most important is to individualize the treatment goal for each patient. Some tolerate higher HCT than others. Some report feeling better in a certain range of HCT. While the statistical risk factors matter, actual symptoms matter even more.

Ultimately, this is about shared decision making. If a female with PV is more comfortable setting the HCT goal at 42/43% based on the current evidence and treatment practices, then that is what the goal should be. It is each patient's prerogative to set their treatment goals, working collaboratively with their provider.

All the best.

[LittleLuna in reply to hunter5582]

Thanks Hunter.

Early stages of venesection treatment but so far I feel better with hct below 40. Will see as time goes on but certainly feels better

[hunter5582 in reply to LittleLuna]

Gald to hear you feel better. It is certainly a case-in-point that we are each different. If my HCT dropped below 40, I would be feeling the impact of anemia.

[LittleLuna in reply to hunter5582]

think my B12 is bit low but see specialist next week so going to ask of they will run some extra bloods. Feeling bit worse this week but while 36-39 hct I felt not too bad.

Think its climbing so fatigue kicking in a bit but who knows with this PV, its a learning curve for sure

Hope all good with you

[hunter5582 in reply to LittleLuna]

I am doing well, thanks. Next week is the week of many heart scans. We will see what is up with that.

Definitely check into the Vit B/folate levels. This deficiency can have significant negative impact when present. I have to take a supplement due to chronic Vit B-deficiency likely related to long-term Nexium use.

[K-itty in reply to hunter5582]

Hunter always has so much knowledge! I unfortunately do not respond well with HCT counts above 40...for me my best range is in the mid 30s. Higher than that and all the symptoms I've learned to recognize that go with my PV, return. Again, it's all individual and working with your specialist.

[Looolooo]

Thank you Hunter. Littleluna - I also feel better around 40 but my doc refuses to see this as my own personal target. However interferon is working and hovering at 43 at moment, and feeling OK, so hopefully will stay that way.

[Orangeboykitty]

I'm in Israel and the target here is also 45.

[ainslie]

Dr Spivak explains rather well why women should be less, he mentioned it again at the Oct doc to doc’s conference in NY. If I remember correctly there is a logical reason which he often demonstrates clearly at conferences.I don’t remember the details but a few phrases stood out such as women are not small men and that women have a tenth of the testosterone men have. There was a lot more science to it than that but I didn’t note it. No doubt the vid or paper will be on the internet somewhere. Dr Spivak is pretty smart and well respected so maybe worth taking it seriously ie 42 for women.

[Looolooo]

Thank you Ainslee. Maz - ate you able to locate that paper please?

[Mazcd Partner MPNVoice in reply to Looolooo]

Hi Looolooo, sorry I am afraid I am unable to locate it. Maz

[Imkerin]

Hi, I'm in UK under MPN service at UCLH. At least one of the consultants there works to a count of under 43 for females.

[Looolooo in reply to Imkerin]

Thank you. Are you able to name consultant please?

[Imkerin in reply to Looolooo]

Jonathan Lambert

[user2021a]

I was on 45 but had blood clots (that was how I was diagnosed with PV). My target has been reduced to 40. Feel ok with it at 40 but if it goes much below this awful with anaemia.

[KLCTJC]

My goal from MD Anderson and local onc is 45. I am lucky as it takes about 5 months for me to need a phlebotomy because my last one I felt so drained. I will likely need one in 2 weeks since I was at 44 in January. I am just hoping on Besremi I won’t. I will be on a higher dose when I go for labs. But I know of others that goal is 42 and I think it is like Hunter said. You and your doctor can decide. I actually have a patient who has PV and sees my local onc and he likes to be lower and they basically met in the middle. But he likes to have phlebotomy every few weeks.

[Solyesh]

This always fascinates me- the difference in reference ranges and individual doctor/patient acceptable data..our local reference range for HCT for men is 41-53 (updated from 39-50 a few years ago). Had never paid attention to my HCT given the ET diagnosis but my MPN specialist at my appointment yesterday also pointed out that the Peg had brought down my HCT as well..looking back there were a number of readings that were quite high (46.8/48.8/49.5) but not consistently so (most readings have been 40-42) and the BMB pointed squarely to ET but just interesting on how MPNs can just affect across all lines...

[ritaandscooter1]

It completely depends on who is treating you in the US. My doctors use the 45 HCT threshold. My earlier doctor used the 42 mark. Kerry

[Lena70 in reply to ritaandscooter1]

My doctor is using 45 as well.

[Looolooo]

It looks to me like there needs to be some stronger advice to docs on what they should be working to and why.....

[ainslie in reply to Looolooo]

indeed, MPN. Stuff IS science so on a thing like Hct level and similar the docs should all agree

[Elizka]

Hi,

Both of my HEMs-Stanford and Uc Davis Health recommend 42 or lower of women. We have smaller vessels and typically women without an MPN have lower HCT levels.