Diagnostic criteria for idiopathic hypereosinophilic syndrome (iHES)
| 1. Persistent peripheral blood hypereosinophilia (eosinophil count ≥ 1.5 × 109/L and ≥ 10% eosinophils)* |
| 2. Organ damage and/or dysfunction attributable to tissue eosinophilic infiltrate† |
| 3. No evidence of a reactive, well-defined autoimmune disease or neoplastic condition/disorder underlying the hypereosinophilia |
| 4. Exclusion of lymphocyte variant hypereosinophilic syndrome‡ |
| 5. Bone marrow morphologically within normal limits except for increased eosinophils |
| 6. No molecular genetic clonal abnormality, with the caveat of clonal hematopoiesis of indeterminate potential (CHIP) |
| The diagnosis of iHES requires all 6 criteria. |
| 1. Persistent peripheral blood hypereosinophilia (eosinophil count ≥ 1.5 × 109/L and ≥ 10% eosinophils)* |
| 2. Organ damage and/or dysfunction attributable to tissue eosinophilic infiltrate† |
| 3. No evidence of a reactive, well-defined autoimmune disease or neoplastic condition/disorder underlying the hypereosinophilia |
| 4. Exclusion of lymphocyte variant hypereosinophilic syndrome‡ |
| 5. Bone marrow morphologically within normal limits except for increased eosinophils |
| 6. No molecular genetic clonal abnormality, with the caveat of clonal hematopoiesis of indeterminate potential (CHIP) |
| The diagnosis of iHES requires all 6 criteria. |
Preferably a minimal duration of 6 months if documentation is available.
Hypereosinophilia of uncertain significance has no tissue damage, but otherwise fulfills the same diagnostic criteria.
An abnormal T-cell population must be detected immunophenotypically with or without T-cell receptor clonality by molecular analysis.