The myeloproliferative disorders consist of polycythemia vera, chronic myelogenous leukemia, agnogenic myeloid metaplasia, and essential thrombocythemia. All these disorders are thought to result from a hematopoietic stem cell lesion. Diagnosis depends on findings from the blood, bone marrow, physical examination, and the exclusion of other causes of erythrocytosis. Specific criteria have been established by the Polycythemia Vera Study Group for the diagnosis of p. vera. The diagnosis is established if the patient fulfills all three major criteria or the first two major criteria and any two minor criteria.
Serum erythropoietin is either absent or found in very low levels in patients with p. vera.
In most patients there is no stainable iron found in the bone marrow. There is no staging system for this disease. Untreated polycythemia vera means that a patient is newly diagnosed and has had no prior treatment except supportive care. Marrow fibrosis is often a prominent feature. There is no staging system for this disease.