Diagnosis of JAK2 positive polycythemia requires the presence of both criteria.
Criteria for JAK2 positive polycythemia:
(1) presence of JAK2 mutation
(2) one of the following:
(2a) elevated hematocrit (male > 52%; female > 48%)
(2b) increased red cell mass (>125% of the predicted value)
Diagnosis of JAK2 negative polycythemia requires one of the following:
(1) presence of (A1, A2 and A3) AND (A4 or A5).
(2) presence of (A1, A2 and A3) AND (>=2 B criteria).
Criteria for JAK2 negative polycythemia: A1 to A3
(A1) one of the following:
(A1a) elevated hematocrit (male >= 60%; female > 56%)
(A1b) increased red cell mass (>125% of the predicted value)
(A2) absence of JAK2 mutation
(A3) exclusion of secondary erythropoiesis (normal arterial oxygen saturation and absence of elevated serum erythropoietin)
Criteria for JAK2 negative polycythemia: A4 or A5
(A4) palpable splenomegaly
(A5) acquired genetic abnormality in hematopoietic cells, excluding BCR-ABL
Criteria for JAK2 negative polycythemia: B1 to B4
(B1) thrombocytosis (> 450,000 per µL)
(B2) absolute neutrophilia (> 10,000 per µL in nonsmokers; > 12,500 in smokers)
(B3) splenomegaly on imaging studies
(B4) endogenous erythroid colonies OR low serum erythropoietin
