There are a number of reasons other than progression that reactive thrombocytosis can occur. Retesting in two weeks makes sense. I expect your hematologist will want to run some additional testing as well. Meanwhile, do not assume anything as your imagination is likely worse than the reality of what is going on. Note that I have seen sharp spikes in platelets due to injury-inflammation-illness. This has always resolved when the cause resolved.

Hello Renee,
I'm glad that to see that your question prompted a response with good information from the myMPNteam.
Speaking as a matter of personal experience, I understand how frightening it is to have such high platelet counts. Here's my story.
In 2011, just before turning 60, I was diagnosed with ET after a routine CBC showed platelets at 1.2 million. I went on hydroxyurea immediately. For the next 11 years, my platelet numbers varied widely, and my hematologist tried to chase the numbers with varying dosages of HU, without much success. My highest count was 1.6 million, and I've often been over 1 million. It is definitely scary (despite my husband joking that I'm finally a millionaire!).
In 2021, I was diagnosed with the CALR mutation, which is associated with higher platelet counts, many of which are immature or defective (and thus, to me, less scary). With that knowledge, I approached both my hematologist and my MPN specialist with the idea of going off HU to see what would happen. I got their blessing for the experiment.
I stopped HU in August 2022, taking only baby aspirin since. The result? My platelet counts have leveled out, remaining reliably (and stubbornly) in the 900s. And there they've stayed -- until last month, when the clinical trial drug I'm on finally dropped them into the 700s.
My advice? Relax and try not to focus on the numbers alone. See an MPN specialist, if you haven't already. Find out if you have a mutation (simple blood test). Consider a bone marrow biopsy, if you haven't had one already; the BMB is better at showing the extent and changes in fibrosis and thus can better assess for progression.
Most importantly, take care of yourself and enjoy your life!
For many of us with MPNs, the disease is little more than just background noise. I wish the same for you, Renee.

Hi Renee,

I understand your worries, they are normal.
You have many good answers here already.
Studies show increases in platelets are not correlated with disease progression, they are not an indicator of the illness worsening.
They happen for many reasons, some of which might have nothing to do with your MPN. As Steve already pointed out, physical injury, infections, significant levels of inflammation (as in autoimune flares), surgery, even some internal bleeding, all can raise your platelet levels.
Depending on the mutation you have, some mutations do tend to be associated with higher platelet numbers.

As for the other value being elevated, that could mean that you might have some anemia, for example. Your specialist should explain these values to you, as otherwise one ends up worrying.
Psychological stress by itself is not known to significantly elevate platelets, so do not add this worry to your list.
If you manage situations via allowing some worry about platelets being elevated and wanting clear answers, then use what coping strategies work best for you.
If you already had a bone marrow biopsy at your diagnosis, that is good. If you didn't, and you can have a bone marrow biopsy, that would be good to have, just to know how your bone marrow looks.

Hopefully you will have good answers from your MPN specialist.

You don’t say how long you’ve been ill or if you are already taking meds, but in my 24+ years with ET and now PV, periodically platelets or other counts would rise and medication adjustment was required. Then on as usual, until the next time.

Kind of the nature of the beast with these MPN’s.

Deep breaths, try not to panic. There are many of us here who have ridden out the waves and managed our illlness well for decades.

All the best to you, and pls keep us posted as your journey may help someone else.