Hi - I have been diagnosed with chronic eosinophilic leukemia and the test that diagnosed it was next generation sequencing test called MMP75 at my hospital but different planes have different tests. This tests for all types of jak2 mutations plus more. I mention this because my first hematologist said i did not have the jak2 mutation but my second hematologist k ew about this other specialized test and unfortunately it showed I had a very rare jak2 mutation and I was undiagnosed with CEL. I also want to mention that my doctor told me it is not good to have high eosinophils so we use various medications to keep them below 2000 (jakifi and hydrea). Now you might have a different kind of CEL with different treatments, but I wanted to share my experience since many places do not perform the special test I mentioned. Good luck and I’m happy to share any other information I have.