"Elkhorn" (abnormally shaped) megakaryocytes can be found in a bone marrow biopsy. This was the gold standard for diagnosis before genetic testing for driver mutations was common.

BMB is done a little less often now, though many docs feel it is useful to nail the diagnosis as well as to assess the level of fibrosis, if any, in the bone marrow.

A high platelet count that rises incrementally over a period of years where other blood counts remain normal + a positive test for one of the driver mutations = diagnosis. A small percentage of patients may be neg for the 3 driver mutations, which usually requires a bone marrow biopsy to look for the elkhorn megakaryocytes.

If I were worried about pushing buttons with a doctor, it might be because a) I did not have the right doc for me and my questions, or b) I was resisting a diagnosis.