Due to the insidius nature of many of the myeloproliferative neoplasms, including PV, patients are diagnosed before symptoms appear. Abnormal laboratory results demonstrated in many patients with PV include:
- Erythrocyte count > 6.0 x 1012/L
- Hemoglobin >16.5 g/dL (males) >16. g/dL (females)
- Hematocrit >49% (males) and >48% (females)
- WBC count >12.0 x 109/L
- Platelet count >450 x 109/L
The WHO states that bone marrow morphology is a major diagnostic criterion (hypercellularity with prominent erythroid, granulocytic, and megakaryocytic proliferation), along with JAK2(V617F) or exon 12 mutation. At least 95% of patients with PV will possess the JAK2(V617F) gene mutation, which helps to distinguish PV from other causes of erythrocytosis such as secondary polycythemia or relative polycythemia.
However,a patient may still be diagnosed with PV, if the patient meets the previously-estabished hemoglobin threshold of 18.5 g/dL in men or 16.5 g/dL in women and shows a JAK2 mutation, as well as a decreased serum erythropoietin level.