Inclusion Criteria:

1. Patients with an elevated hemoglobin concentration (>18 in males and >16 in females)
and who are suspected to have congenital or acquired primary polycythemia

2. Patients with a persistent thrombocytosis (>400,000) that does not have an obvious
secondary cause

3. Patients with a bone marrow biopsy that shows increased cellularity and fibrosis

4. Patients where there is clinical concern for primary myelofibrosis, such as anemia in
combination with leukocytosis, thrombocytosis, splenomegaly and/or a
leukoerythroblastic blood smear

5. Patients with thrombosis at unusual sites, such as Budd-Chiari syndrome, can have
early PV before hemoglobin is elevated, these patients will also be included.

Exclusion Criteria:

1. Subjects who have a known acquired cause of polycythemia (increased
hemoglobin/hematocrit) such as people living in high altitudes (in excess of 14,000
feet), subjects with heart disease, left to right heart shunt, severe hypoxia or
severe pulmonary disease will be excluded from this study.

2. Subjects with a known acquired cause of thrombocytosis.

3. Subjects will be excluded if they cannot demonstrate decision making capacity
sufficient to agree or decline the blood drawing or use of their blood for the study.