Polycythemia Vera

The World Health Organization (WHO) requires three separate criteria to diagnose polycythemia vera:

Criteria 1: Blood test showing high red blood cell count:

Red blood cells may be measured as:

• High hemoglobin count (protein found in red blood cells).
• High hematocrit levels (percentage of red blood cells).
• High blood volume (red cell mass).

Criteria 2: Bone marrow biopsy showing either:

• Excess of blood cells in the bone marrow, or
• Excess of mature megakaryocytes (the cells that make blood platelets).

Criteria 3: The third criteria can be met by showing either:

• Molecular testing showing the presence of the JAK2 gene mutation, or
• Blood test showing very low levels of erythropoietin (a hormone produced by your kidneys to stimulate red blood cell production).