That is a somewhat complex question. It depends on which symptoms you are talking about. There is no linear relationship between platelet level and risk of thrombosis. There is no particular "safe" number that needs to be a target for all with ET. There is a linear relationship between platelet levels and risk of hemorrhage. The higher the level, the greater the risk. For people with platelet levels well over 1 million, and sometimes lower, there is risk of Acquired von Willebrand Disease, a bleeding disorder. There is also risk of microvascular symptoms but this has more to do with how the platelets behave than how many of them there are.

There is also the issue of the secondary or constitutional symptoms people with ET experience, fatigue, pruritis, night sweats, etc. Many of these symptoms are related to the overproduction of inflammatory cytokines. The symptoms are not related to the number of platelets but relief may correlate with a lower platelet level. Cytoreductive treatments may also lower the level of inflammatory cytokines and provide symptom relief.

The more detailed answer involves an assessment on a case-by-case basis. We are all different in how the MPN presents. The presence of non-driver mutations, co-occurring medical conditions, and other factors may influence symptom presentation. It is not just about how many platelets there are.

Wishing you all the best.

Wow Steve, thank you so much for that answer. It really helps me understand a little more about this disease!

Hi Patty
My platelets have been as high as 970 and as low as 490. No symptoms high or low.
All I will say I was very stressed our when they were 970.
Best wishes
Lyn

Thank you Steve for sharing this info. I get stuck on the number and then panic if it goes up. Slowly but surely, I am gaining an understanding of ET.