From the Guidelines
The diagnosis of Polycythemia Vera (PV) in a patient presenting with erythrocytosis involves a comprehensive evaluation to confirm the presence of the disease and assess its severity, with the presence of JAK2 mutation and elevated hemoglobin, hematocrit, or red cell mass being the two major criteria 1.
Diagnostic Criteria
The diagnostic criteria for PV include:
- Major criteria:
- Laboratory evidence of increased hemoglobin, hematocrit, or red cell mass
- Presence of a JAK2 mutation
- Minor criteria:
- MPD-consistent bone marrow histology
- Serum erythropoietin level below the reference range for normal
- Presence of endogenous erythroid colonies Diagnosis of PV requires either the presence of both major criteria and at least one minor criterion or the presence of the first major criterion and at least two minor criteria 1.
Evaluation Process
The evaluation process for PV involves:
- Initial assessment: Complete blood count (CBC), blood smear, and serum erythropoietin level to evaluate for erythrocytosis and rule out secondary causes
- JAK2 mutation testing: To confirm the presence of a JAK2 mutation
- Bone marrow biopsy: To evaluate for MPD-consistent bone marrow histology and rule out other myeloproliferative neoplasms
- Endogenous erythroid colony formation: To evaluate for the presence of endogenous erythroid colonies The diagnosis of PV should be made in accordance with the revised WHO criteria, which include the presence of a JAK2 mutation and elevated hemoglobin, hematocrit, or red cell mass, as well as the absence of secondary causes of erythrocytosis 1.
From the Research
Diagnostic Approach
The approach to diagnosing Polycythemia Vera (PV) in a patient presenting with erythrocytosis involves several steps:
- Erythrocytosis (hemoglobin >16.5 mg/dL in men or >16.0 mg/dL in women) is a required diagnostic criterion 2
- The presence of a JAK2 gene variant helps distinguish PV from secondary causes of erythrocytosis, such as tobacco smoking or sleep apnea 2, 3
- Morphologic confirmation by bone marrow examination is advised but not mandated 3
- Serum erythropoietin (EPO) level can be elevated or decreased in PV, and further testing such as the JAK-2 gene mutation test is necessary to confirm the diagnosis 4
Diagnostic Criteria
The World Health Organization (WHO) consensus criteria for diagnosing PV demand the presence of two major criteria and one minor criterion or the presence of the first major criterion and two minor criteria 4
- Major criteria include the presence of a JAK2 mutation and bone marrow morphology consistent with PV
- Minor criteria include decreased EPO level, leukocytosis, and thrombocytosis
Risk Stratification
Two risk categories are considered in PV: high (age >60 years or thrombosis history) and low (absence of both risk factors) 5, 3, 6
- High-risk patients are at increased risk of thrombosis and may benefit from cytoreductive therapy
- Low-risk patients may be managed with phlebotomy and aspirin therapy alone
Treatment
The main goal of therapy in PV is to prevent thrombohemorrhagic complications:
- All patients with PV require phlebotomy to keep hematocrit below 45% and once-daily or twice-daily aspirin (81 mg), in the absence of contraindications 5, 3, 6
- Cytoreductive therapy is recommended for high-risk PV and may be considered for low-risk disease with persistent symptoms or high thrombosis risk 5, 3, 6