Essential thrombocytosis laboratory tests

Diagnostic criteria
The diagnosis of essential thrombocytosis requires the presence of a persistent thrombocytosis of greater than 600 x109/L in the absence of an alternative cause.

The following revised diagnostic criteria for essential thrombocytosis were proposed in 2005. The diagnosis requires the presence of both A criteria together with B3 to B6, or of criterion A1 together with B1 to B6.

But the Philadelphia chromosome may be present in up to 10% of cases. Patients withe the Philadelphia chromosome have a potential for the development of acute leukemia, especially acute lymphocytic leukemia.
 * A1. Platelet count > 600 x 109/L for at least 2 months
 * A2. Acquired V617F JAK2 mutation present
 * B1. No cause for a reactive thrombocytosis
 * normal inflammatory indices
 * B2. No evidence of iron deficiency
 * stainable iron in the bone marrow or normal red cell mean corpuscular volume
 * B3. No evidence of polycythemia vera
 * hematocrit < midpoint of normal range or normal red cell mass in presence of normal iron stores
 * B4. No evidence of chronic myeloid leukemia
 * B5. No evidence of myelofibrosis
 * no collagen fibrosis and ≤ grade 2 reticulin fibrosis (using 0–4 scale)
 * B6. No evidence of a myelodysplastic syndrome
 * no significant dysplasia
 * no cytogenetic abnormalities suggestive of myelodysplasia