Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (351 page)

   Major criteria

   Hemoglobin >18.5 in men, >16.5 in women, or other evidence of increased red cell mass.

   Presence of V617F JAK2 mutation in exon 14, or other functionally similar mutation such as JAK2 exon 12 mutation.

   Minor criteria

   Bone marrow biopsy showing hypercellularity for age with trilineage growth (panmyelosis) and with prominent erythroid, granulocytic, and megakaryocytic proliferation.

   Serum erythropoietin level below the reference range of normal.

   Endogenous erythroid colony formation in vitro (not generally available in clinical laboratories).

The diagnosis requires the presence of
both
major criteria and
one
minor criterion or the presence of the first major criterion with two minor criteria. The first major criterion (high RCM) may be missed in patients with gastrointestinal bleeding.

   Who Should Be Suspected?

   Patients found to have an elevated Hb and Hct (the disease may be asymptomatic for long time) that cannot be explained otherwise.

   Mostly middle aged to elderly patients (median age at presentation is sixth decade).

   Patients with a history of familial polycythemic disorders and elevated Hb/Hct.

   Patients with otherwise unexplained thrombotic or bleeding events. The course of PV is characterized by thrombotic events, frequently in splanchnic vessels.

   Patients with splenomegaly of unknown etiology.