As a follow up to my question, I searched for diagnostic criteria for PV (since they kept emphasizing that DIAGNOSTIC criteria is a hematocrit over 32." They kept using "32" as some magical number. I know that internet resources aren't always accurate, but EVERY paper I have found in the peer-reviewed literature states that one of the major diagnostic criteria for PV is: "Hemoglobin >16.5 g/dL in men and >16 g/dL in women, or hematocrit >49% in men and >48% in women, or red cell mass >25% above mean normal predicted value" (reminder, my hemoglobin today was 10.7, and hematocrit 33, my red cell mass has never been studied." So, where did this magical number of 32 come from? And, does it make sense considering that value would make me anemic (not polycythemic)? Not sure if this is the case, but OLD criteria (from 1970 group), included as one of the major diagnostic criteria as "Category A criteria are as follows: Total red blood cell mass ≥36 mL/kg in males or ≥32 mL/kg in females" I'm wondering if I was literally just diagnosed with PV based on the WRONG measurement (as I have never had red cell mass measured), from an old set of criteria. This would explain the PV diagnosis, which is seemingly contradictory with my (albeit slightly) anemic hemoglobin/hematocrit. Any thoughts on this explanation, or, just in general about if/ow a definitive diagnosis of PV can be made based on just the JAK2 mutation and LOW RBCs?