Table 3.
T2 High Versus T2 Low Asthma Biomarkers
| T2 Biomarkers | |
|---|---|
| T2 High | T2 Low |
| AEC ≥ 150/uL | AEC < 150/uL |
| FeNO ≥ 25PPB | FeNO < 25PPB |
Notes: AEC: AEC is the “Absolute Eosinophil Count” in peripheral blood. ERS/ATS guidelines suggest an AEC T2 cutoff of ≥150 eosinophils/ul as T2 high to guide anti-IL-5 initiation in adults with severe asthma and a history of severe and asthma exacerbations.52 FeNO: ATS guidelines state that high FeNO levels (defined as >25 ppb in adults) are used to determine the T2 high status of a patient with severe asthma.52 ppb is parts per billion. Caveats: Clinical phenotyping (ie age, age of asthma onset, allergic sensitization, obesity, etc.,) should be combined with T2 biomarkers in determining asthma phenotype. In addition, phenotypes are not fixed and can change in response to environmental triggers (ie respiratory viral infections, tobacco smoke, air pollution).52