Table 3.
Initial assessment of the patient with hypereosinophilia
| All patients with confirmed HE | Comments |
|---|---|
| Comprehensive history and physical examination | Including prior eosinophil counts, medications, travel/exposure history |
| Complete blood count with differential and smear* | Dysplastic eosinophils, other lineage involvement, and/or presence of myeloid precursors are suggestive of (but not diagnostic for) MHES |
| Routine chemistries, including liver function tests* | To assess end organ involvement |
| Quantitative serum immunoglobulin levels | IgE levels are typically elevated in a variety of conditions (ie, LHES, EGPA, parasitic infections, and some immunodeficiencies); IgM levels are elevated in LHES and episodic angioedema and eosinophilia |
| Serum tryptase and B12 levels | Elevated serum B12 levels can be seen in many myeloid neoplasms; elevated serum tryptase is near universal in PDGFRA and KIT-associated disease |
| T- and B-cell receptor rearrangement studies*; lymphocyte phenotyping by flow cytometry* (see Carpentier et al11)† | Clonal and/or aberrant T-cell populations are characteristic of LHES and some types of lymphoma. Clonal B cells are suspicious for B-cell neoplasm, including pre–B-cell acute lymphoblastic leukemia in children/adolescents. |
| Serum troponin,* electrocardiogram, and echocardiogram | If abnormal, cardiac MRI should be considered |
| Chest/abdomen/pelvis CT* | To assess for splenomegaly, lymphadenopathy, asymptomatic pulmonary involvement, and occult neoplasms |
| Biopsy of affected tissues (if possible)* | Cardiac tissue involvement can be patchy, limiting the utility of cardiac biopsy |
| Selected patients with HE/HES | |
| Pulmonary function tests* | Any patient with suspected pulmonary involvement or abnormal findings on chest CT |
| Bone marrow aspirate and biopsy* | All patients with AEC >5.0 × 109/L and/or features suggestive of LHES or MHES; patients with clear diagnoses, such as EGPA or parasitic infection, may not need bone marrow testing despite AEC >5.0 × 109/L |
| Testing for BCR::ABL1, FIP1L1::PDGFRA, and translocations/mutations involving PDGFRB, JAK2, FGFR1, and KIT | Testing should be guided by results of initial testing and bone marrow examination; all patients with elevated serum tryptase and/or B12 levels should be tested for FIP1L1::PDGFRA |
| NGS myeloid panel; targeted or whole-exome sequencing; other genetic testing | Depending on initial evaluation |
| PET scan,* EBV viral load | Particularly in patients with suspected LHES |
| Other testing for secondary causes | As indicated by clinical history and physical examination |
*
Can be dramatically affected by corticosteroid therapy.
†
Not all patients with LHES will have clonal or aberrant T-cell populations detectable by routine testing.
CT, computed tomography; EBV, Epstein-Barr virus; EGPA, eosinophilic granulomatosis and polyangiitis; MHES, myeloid variant hypereosinophilic syndrome; MRI, magnetic resonance imaging; NGS, next-generation sequencing; PET, positron emission tomography.