Table 38.1. Criteria for diagnosis of polycythemia vera

Table 38.1. Criteria for diagnosis of polycythemia vera.^a

Category A
(1) Significantly elevated red cell mass
(2) Arterial blood oxygen saturation ≥92%
(3) Splenomegaly
Category B
(1) Thrombocytosis >400,000 μL
(2) Leukocytosis >12,000 μL
(3) Increased leukocyte alkaline phosphatase score in absence of fever or infection
(4) Serum vitamin B₁₂ level greater than 900 pg/mL or vitamin B₁₂-binding capacity greater than 2200 pg/mL

^a Diagnosis of polycythemia vera if A1 + A2 + A3 or A1 + A2 + any two factors from category B.