Good morning, @onthejoedock. When there is a mutation with the JAK2 gene, it can interfere with the proper production of all the blood cells…white, red and platelets. Some people will have only one issue such as essential thrombocythemia (ET) with the overproduction of platelets or Polycythemia vera (PV) the over production of red cells, though there are more conditions associated with this.

I thought you might appreciate this article which explains the involvement of the JAK2 gene with your husband’s PV and ET.
https://www.verywellhealth.com/jak2-mutation-5217909?utm_campaign=687680030-1175379671227571&utm_source=bingpaid&utm_medium=paid&utm_content=73461429226290&utm_term=o-jak2%20mutation-jak2%20mutation&msclkid=daabcf8367f4199652dcaa4393a62de9
It’s encouraging to hear your husband is starting to adapt to the HU. It can take a while and like I mentioned before, the doctor may consider lowering Joe’s dosage when his blood numbers level out.
It’s also important to have a good liquid intake during the day. This helps with flushing out waste from the body, regulating body temperature, and helping the brain function. If Joe isn’t drinking enough that might explain some of the confusion and exhaustion at the end of the day…just a thought. I know when I was on quite a few meds
I could tell when I hadn’t had enough to drink. I learned through my nurses at Mayo to drink room temperature water. It goes down a lot easier so I drink more. I’m no longer on meds but I still find myself drinking at least 64 ounces daily.

Fingers crossed for Joe’s next blood work! I hope his numbers are back to normal. ☺️