Proposed modified criteria for the diagnosis of polycythemia vera (PV).
| A1 | Raised red cell mass (> 25% above mean normal predicted value, or PCV ≥ 0.60 in males or 0.56 in females) |
| A2 | Absence of cause of secondary erythrocytosis |
| A3 | Palpable splenomegaly |
| A4 | Clonality marker, i.e. acquired abnormal marrow karyotype |
| B1 | Thrombocytosis (platelet count > 400 × 109/L) |
| B2 | Neutrophil leucocytosis (neutrophil count > 10 × 109/L; > 12.5 × 109/L in smokers) |
| B3 | Splenomegaly demonstrated on isotope or ultrasound scanning |
| B4 | Characteristic BFU-E growth or reduced serum erythropoietin |
| A1 + A2 + A3 or A4 establishes PV | |
| A1 + A2 + two of B establishes PV | |
| A1 | Raised red cell mass (> 25% above mean normal predicted value, or PCV ≥ 0.60 in males or 0.56 in females) |
| A2 | Absence of cause of secondary erythrocytosis |
| A3 | Palpable splenomegaly |
| A4 | Clonality marker, i.e. acquired abnormal marrow karyotype |
| B1 | Thrombocytosis (platelet count > 400 × 109/L) |
| B2 | Neutrophil leucocytosis (neutrophil count > 10 × 109/L; > 12.5 × 109/L in smokers) |
| B3 | Splenomegaly demonstrated on isotope or ultrasound scanning |
| B4 | Characteristic BFU-E growth or reduced serum erythropoietin |
| A1 + A2 + A3 or A4 establishes PV | |
| A1 + A2 + two of B establishes PV | |