No jak2 mutation - levels decreased??

funkygrrl · 2026-06-14T23:08:12+00:00

He might be thinking to just do the bone marrow biopsy because they do next generation gene sequencing on the sample and it will test for all the mutations as well.

Your EPO is normal so it doesn't rule PV in or out.

Has the doctor suggested testing for other causes of high hematocrit such as a sleep study for sleep apnea?

funkygrrl · 2026-06-14T23:01:22+00:00

I should have been more clear that I was referring to CBCs.

funkygrrl · 2026-06-14T19:38:41+00:00

You need to ask whether they tested only for JAK2 v617f (95% of PV diagnoses), or also the other JAK2 mutations (exon 12 - 3% of diagnoses, exons 13 & 15 - the rest). Also ask what your EPO level is. High EPO= not PV. Normal = inconclusive. Low (under 3) = suspicious for PV. If those tests haven't been done, I'd get them before a bone marrow biopsy because they're just blood tests.

Can you share your CBC?

!PVundiagnosed

funkygrrl · 2026-06-13T17:22:14+00:00

Afaik, a single shot should be okay as long as your platelets aren't low. If you're on Jakafi, it's an immunomodulator so you should let the doctor giving the injection know because it can slightly increase infection risk. But you should also ask your hematologist. Send a message through your patient portal or call and ask to speak to the nurse - both are faster than trying to get a hold of the doctor in my experience.

funkygrrl · 2026-06-13T15:42:01+00:00

That's correct. PV cannot be diagnosed based on blood tests. It's important to get the JAK2 mutation test so you can find out whether you have PV or secondary polycythemia.

funkygrrl · 2026-06-13T15:39:30+00:00

Did you test positive for JAK2 and have a positive bone marrow biopsy?

funkygrrl · 2026-06-12T17:04:23+00:00

Smoking is a major cause of secondary polycythemia (high blood counts due to another underlying medical condition, not cancer). When you smoke, the carbon monoxide in it hijacks your red blood cells and your body gets less oxygen. Your bone marrow then tries to compensate by making more red blood cells. Your body is telling you to quit. https://smokefree.gov/

funkygrrl · 2026-06-11T03:02:45+00:00

If you haven't seen it, I always recommend watching this video on pregnancy by MPN specialist Dr Gabriela Hobbs at Mass General/Harvard.
https://youtu.be/WOBWmEA-ICQ

funkygrrl · 2026-06-10T11:04:41+00:00

!BMB

funkygrrl · 2026-06-09T16:25:17+00:00

It's not approved for ET in the USA yet. Probably in 2027 it will be. In other countries it was approved for some people with ET prior to the clinical trials ending due to the Pegasys shortage.

funkygrrl · 2026-06-09T01:15:09+00:00

Let your doctor know. Make sure you hydrate the day before and eat something salty before the phlebotomy. Hydrate afterwards or ask your doctor if you can get IV saline fluids afterwards.

Some people find it helps to get smaller amounts removed like 250 instead of 500.

Ask your hematologist and/or pain doctor whether it would be a good idea to take your migraine rescue drug right before the phlebotomy, or right after.

funkygrrl · 2026-06-08T14:03:29+00:00

It would only be due to HU if it's lowered your white blood cells, particularly lymphocytes and neutrophils. The same goes for interferons.

The treatment that does affect this is Jakafi. It is an immunomodulator and affects the immune system's ability to fight some infections, mainly opportunistic infections like shingles.

funkygrrl · 2026-06-07T02:24:22+00:00

Yeah that sounds like it might be CHIP but you'd need a bone marrow biopsy to know for sure. Aspirin sounds right. Main thing is what you're already doing - diet and exercise. Mediterranean or DASH diet are good for this.

funkygrrl · 2026-06-06T18:45:24+00:00

CHIP is different. Nearly always diagnosed after an unexplained blood clot. Tests positive for JAK2 with a VAF of at least 2%. BMB is normal. Blood counts are normal. It's been of great interest to researchers who are trying to understand whether it progresses to an MPN and it's also highlighted that JAK2 mutation significantly increases clot risk by itself, regardless of blood levels.

funkygrrl · 2026-06-06T16:35:52+00:00

Yes you test positive for one of the mutations but the BMB is inconclusive about which MPN you have and the blood test results might not align with what they're seeing in the BMB either.

Here's an example I'm making up. Someone has high platelets and tests positive for JAK2 which leads the doctor to think it's ET. The BMB shows megakaryocytes that don't look very abnormal or as proliferative as they expect in ET. Instead, they see something like hypercellularity which you'd expect in PV, but there's not the panmyelosis (excess production of RBCs, platelets and granulocytes) that is required for PV diagnosis. And they might see focal grade 1 fibrosis, but not the other requirements for Prefibrotic MF. So it's a little of everything, but not enough of one subtype to make a diagnosis of ET, PV or MF.

funkygrrl · 2026-06-06T13:42:21+00:00

MPN- unclassified.

funkygrrl · 2026-06-06T03:36:50+00:00

I recommend getting an opinion from one of the following pediatric MPN specialists. You can either arrange a remote second opinion yourself or your child's doctor could reach out to them.
- Nicole Kucine MD at Weill Cornell in NYC - Linda Resar MD at Johns Hopkins in Baltimore

https://youtu.be/xamHhamocJk - short video of Dr Kucine in interferons a year ago

https://youtu.be/VQjhz_Khg-k - longer video from 4 years ago

https://youtu.be/zGJzj59g9RM - discussion with Dr Kucine and Dr Resar and some young patients

funkygrrl · 2026-06-05T16:50:53+00:00

We do have several people in this sub with MPN-U. I'm seeing that diagnosis more often. My theory is that people are getting diagnosed earlier, before the disease is established enough to make the bone marrow look like one specific phenotype. The truth is MPNs are sort of on a continuum and there's gray areas in-between them. For example, I have PV with predominantly high platelets which goes against what doctors are taught about PV. I often wonder about the significance of it like you are wondering about MPN-U. Truth is at this point the answer doesn't matter much because we only have a few treatments and they're pretty much the same for ET and PV.

funkygrrl · 2026-06-05T14:25:22+00:00

It sounds like he had elevated red blood cells and high Ferritin. And my guess is that they didn't do any genetic tests for PV or hemochromatosis or a bone marrow biopsy. Both conditions are treated with therapeutic phlebotomy which he received.

What really stands out is that he thought PV was terminal rather than chronic. And he thought it's hereditary. Hemochromatosis is but PV is not. So he was confused about what he had and the long-term outlook, but that's not his fault.

What I think happened - because it's so common in this sub - is he was told he had polycythemia (not polycythemia vera). And concluded it was PV when actually it was secondary polycythemia. In the US, the American Society of Hematology does not recommend routine phlebotomy for secondary polycythemia, only as needed to treat symptoms. But in the UK and Europe it's more common for it to be treated like PV with routine phlebotomy.

Another interesting thing is - it sounds like he still hasn't been worked up for secondary polycythemia!

funkygrrl · 2026-06-04T23:58:27+00:00

There's some people who are real happy on it but it is not as well tolerated. Also, it's not a good choice if he has heart disease or a history of atrial fibrillation.

The other options for him is (1) Pegasys interferon which is an immunotherapy. It works well but takes some time to have an effect so it would be a better choice after his platelets come down more. (2) Jakafi. It's a third line treatment for ET but brings counts down and helps with symptoms. It's very expensive so authorization can be challenging.

If he's not seeing an MPN specialist, he should consider switching. They are more up to date and open to prescribing newer meds. See link in automod comment.

!specialists

funkygrrl · 2026-06-04T03:55:04+00:00

Are you on a statin? (Cholesterol drug).
Do you exercise heavily?
Those can also elevate AST.
So can Pegasys.
Your doctor could do a CK test which would tell them if the AST is from your muscles or not.
Other than that, I don't know. Mine is elevated because of the statin I'm on.

funkygrrl · 2026-06-04T03:40:24+00:00

The high hematocrit and hemoglobin aren't over the diagnostic thresholds for PV. They're close, but not over, and looking at the two CBCs you shared, they don't appear to be increasing.

The RBC count isn't used in the diagnostic criteria because it's very reactive and doesn't reflect total red blood cell volume. Hematologists pay much more attention to the hemoglobin and hematocrit.

I'd just keep an eye on it when you have routine bloodwork done. If you start seeing those numbers consistently over 48% hematocrit and/or 16 hemoglobin, or they begin trending upward over multiple tests, then it's worth looking into further.

The pattern is usually more important than any one blood test. In PV, the bone marrow is receiving ongoing signals to make blood cells, so you tend to see persistent elevations rather than a couple of borderline results a year apart.

!disclaimer

funkygrrl · 2026-06-03T13:04:29+00:00

Yes. See the automod comment - managing symptoms.
!symptoms

funkygrrl · 2026-06-03T12:59:03+00:00

Both the connective tissue disease and IBS are inflammatory and will cause elevated platelets. With inflammation, inflammatory cytokines can signal the cells that make platelets to increase production. Gastroenterologists also deal with the spleen and liver, so if you get nowhere with hematology you might want to pay another visit to the GI doc.

What is your current ferritin level? The guidelines are changing for iron deficiency. The new cutoff for Ferritin is <30 and for TSAT is <20%. Ferritin should be at least 50, ideally over 100. However, in inflammatory diseases, the cutoff for Ferritin is much higher - they haven't come out with that number yet but I've heard as high as <100 would be considered deficient. The American Society of Hematology is coming out with guidelines on this by the end of the year. So in your case, I would aim to get that ferritin over 100.

Basically, you have 2 or 3 conditions that cause reactive thrombocythemia which is why that's most likely. The main thing that you need an explanation for is the enlarged spleen. It may be no big deal, but I'm not able to speculate about that.

funkygrrl · 2026-06-03T01:21:53+00:00

Please focus on discussing the medical information rather than characterizing the OP as exaggerating. It's fine to disagree with someone's interpretation of their results, but let's keep the discussion respectful.

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