Hi @bshattuck138 It sounds like Becky has found the sweet spot of balance with the HU she’s taking for her diagnosis of ET. Having no side effects and seeing her platelet level get back under control is a win/win. She may be fortunate and not have an escalation of symptoms. From my understanding, many people don’t.
I’d love to be glib and say, “Don’t go looking for trouble” but I won’t…LOL. Your wife’s doctor will keep an eye on her labs. They’ll look for trends in numbers. Since ET is a generally slowly progressing disease, the labs will indicate whether there are any changes happening. One or two blood tests don’t give a complete picture as our numbers can fluctuate quite a bit daily. But an upward or downward pattern in tests reveals a more accurate picture. Certainly if there are any new changes such as nose bleeds, headaches, dizziness, etc., then she should check in with her doctor.

If you enjoy a little reading, here’s a link to Medical News Today, which has a pretty good article on ET and following it is another on MPNs - myeloproliferative neoplasms, which is the group of diseases where ET is a member.
https://www.medicalnewstoday.com/articles/essential-thrombocythemia#contacting-a-doctor
How often does Becky have labs?