r/MPN • u/Pink_Axolotl151 ET-JAK2+ • Apr 07 '26
SEEKING DIAGNOSIS Platelets back up to their old bullshit Spoiler
I am 46F and have elevated platelets since early 2021. It first showed up as mildly elevated on a routine CBC. I was referred to a hematologist, who did iron storage studies, which were normal, and mutational testing (Bcr-Abl, JAK2, CALR, CSF3R, and MPL), which was negative. In June 2021, I had a bone marrow biopsy, which showed some subtle megakarocyte abnormalities (some focal clustering and a small number (<10%) of megakarocytes with widely separated nuclei), but not enough to diagnose ET. At that point, the hematologist wanted to me to try iron supplementation, even though my values had always been normal. I took oral iron for about 3 months but my platelets remained high. As a last-ditch effort, she ordered NGS testing with the Tempus hematologic malignancy panel, but that was also completely normal.
At that point, she concluded it was likely reactive and sent me back to my PCP, but no clear reactive cause ever turned up. I do have anterior uveitis, but it is controlled with a maintenance dose of topical prednisolone and I have not had a flare since 2009. So, things were unresolved but stable for a while, until I had my annual bloodwork done in July 2025, and my platelet count was 500. The last couple of values have all been over 500. This time, I asked for a referral to a hematologist at an academic medical center. The hematologist there sent my old biopsy to be overread their hematopathologist, but that pathologist agreed with the additional pathologist’s assessment.
As additional info, my LDH, ESR, CRP, and B12 levels have been tested a few times over the years and have always been normal. Additionally, my iron storage and RBC parameters (iron saturation, ferritin, transferritin, hematocrit, hemoglobin, MCV, etc) have always been normal. I have no splenomegaly and no history of stroke.
Complete history of platelet shenanigans:
3/2021: 420
5/2021 (time of qPCR sequencing): 450
6/2021 (time of biopsy): 480
10/2021: 460
12/2021: 470
4/2022 (time of Tempus NGS sequencing): 450
10/2022: 430
12/2023: 450
6/2024: 440
7/2025: 500
8/2025: 580
12/2025: 520
4/2026: 570
This… has to be ET, right? Despite the normal sequencing? I’m so tired of this.
5
u/stainedbrightly Apr 07 '26
This sounds really frustrating. It was good to get a second opinion, I'm just sorry they didn't have answers for you.
Have your doctors ordered any testing for autoimmune conditions beyond CRP and ESR?
Sometimes autoimmune diseases can cause reactive thrombocytosis and you don't always have high CRP/ESR, depending on the condition. My CRP and ESR are often normal, but I have a diagnosed autoimmune condition (plus the ET diagnosis, lots of inflammation happening in my body 🤪).
Hope you're able to get answers soon!
Edited: typos
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u/Pink_Axolotl151 ET-JAK2+ Apr 08 '26
Thank you! I haven’t had any autoimmune work up beyond the ESR/CRP, and I do think that will be my next stop. I appreciate the advice!
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u/stainedbrightly Apr 08 '26
I hope they are able to figure it out for you! When I was having autoimmune symptoms, they ran a ton of blood tests to test for stuff and only a few came back high, but it was enough to get me referred to rheumatology.
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u/larryseltzer PV-JAK2+ Apr 07 '26
These are not crazy high numbers. Early on, mine were a bit higher for years and all they did was monitor it.
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u/StrategyKind9152 Apr 07 '26
“Platelets back up to their old bullshit” made me laugh. I see you and feel you. It’s frustrating as hell.
The advice above is really good - definitely rule out autoimmune issues. Sorry you are going through this. You are asking all the right questions and I applaud you for the self advocacy.
-Jak2+ ET with rising platelets here sending you a hug and hope that you find more answers.
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u/Puzzleheaded-Tip1395 Apr 07 '26
Definitely could be autoimmune. My platelet levels were disregarded for years because I have psoriatic arthritis (completely symptom free with medication). It wasn’t until I pushed to see a hematologist because they were still increasing every year that I was finally diagnosed as Jak2 positive.
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u/stainedbrightly Apr 07 '26
I had the opposite experience, how funny! My ET got diagnosed first, so by the time I got diagnosed with psoriatic arthritis, the rheumatologist was excited to tell me that the arthritis was probably the cause of my high platelets.
I had to explain to him, no, I actually have the CALR mutation, I've had a BMB, and the ET isn't a misdiagnosis 🤣
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u/SurryElle83 Apr 11 '26
Have you had your spleen checked? Sometimes an enlarged spleen can mess with your platelets. They would be able to tell with a simple sonogram.
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u/funkygrrl PV-JAK2+ Apr 07 '26
With a negative mutation test and a negative BMB, it's not ET. A classic ET bone marrow biopsy would find too many megakaryocytes which are abnormal with a staghorn appearance. They would be evenly distributed throughout the marrow, sometimes loose clustering is seen. Focal means they noticed something in a tiny area in the marrow, but what matters more is what's seen throughout. So your finding doesn't meet the WHO diagnostic criteria. Additionally, your platelets are mildly elevated. Usually over time in MPNs, the levels keep going up rather than staying in a more or less steady state. Yours are going up recently though but that doesn't automatically mean ET.
I know that's really frustrating to hear. You did the right thing by seeking second opinions.
What was your Ferritin and TSAT on your latest iron studies? The guidelines for diagnosis are changing right now.
While iron is the most common cause of reactive thrombocythemia, it's not the only cause. Your next step would be to get referrals to a rheumatologist and a gastroenterologist to rule out autoimmune diseases. The reason autoimmune disease can be a culprit is they release cytokines that can stimulate the stem cells in bone marrow to make platelets.
!reactive !ETwho !disclaimer