The assessment tool evaluates if the diagnostic criteria for essential thrombocythemia (ET) are fulfilled based on the World Health Organization's criteria. The input consists of selecting from prescribed options in both major and minor criteria categories.

For major criteria:

- A high platelet count (≥ 450×10^9/L)
- Bone marrow biopsy revealing proliferation primarily in the megakaryocyte lineage, characterized by an increase in large, mature megakaryocytes with hyperlobulated nuclei, without significant increases or shifts in neutrophil or erythroid cells
- Absence of criteria matching other conditions like BCR-ABL1+ chronic myelogenous leukemia, polycythemia vera, primary myelofibrosis, myelodysplastic syndromes, or other myeloid neoplasms
- Detection of mutations in JAK2, CALR, or MPL genes

For the minor criterion:

- Presence of a clonal marker or absence of reactive thrombocytosis evidence

The tool identifies whether the inputs support an ET diagnosis by checking these conditions:

- Major criteria conditions translate into:
  - A true if the platelet count condition is selected
  - B true if the bone marrow biopsy condition is met
  - C applicable when exclusion of other myeloid diseases is specified
  - D valid upon selecting the presence of specific gene mutations

- Minor criterion:
  - E true if a clonal marker presence or reactive thrombocytosis absence is declared

The process compiles these checks to find:

- Diagnostic criteria are met if all of A, B, C, and either D or E are true
- If these combinations are satisfied, the diagnosis aligns with ET, shown by the result "Diagnostic criteria are met." If not, by "Diagnostic criteria are not met."

This calculation aligns patient data with specific criteria, aiding in the systematic identification of essential thrombocythemia.

The World Health Organization (WHO) criteria for essential thrombocythemia is a diagnostic tool designed to identify patients with this specific myeloproliferative disorder. The primary utility of the criteria lies in its ability to differentiate essential thrombocythemia from other similar conditions, thereby guiding appropriate treatment strategies.

The criteria consist of four major components and one minor component. The major components include a platelet count of 450×10**9/L or higher, a bone marrow biopsy showing proliferation mainly of the megakaryocyte lineage with increased numbers of enlarged, mature megakaryocytes with hyperlobulated nuclei, the absence of WHO criteria for BCR-ABL1+ chronic myeloid leukemia (CML), polycythemia vera (PV), primary myelofibrosis (PMF), myelodysplastic syndromes, or other myeloid neoplasms, and the presence of JAK2, CALR, or MPL mutation. The minor component is the presence of a clonal marker or absence of evidence for reactive thrombocytosis.

The diagnostic criteria are met if all four major components are present or if the first three major components and the minor component are present. If these combinations are not met, the diagnostic criteria for essential thrombocythemia are not fulfilled according to the WHO guidelines.

WHO criteria for essential thrombocythemia