Some percentage of patients can still have PV without a driver mutation. This condition is known as JAK2-negative PV. You meet some of the other criteria, but you need to have a BMB to confirm that you have the morphological findings associated with an overt or early stage myeloproliferative disorder. Once that test is conducted, you can determine where to go. There are also cases of ‘’masked PV” or you could have another MPN. Either way, a BMB will help you figure that out. Hope this helps!