How many measurements are needed to be sure?

Approximately 20–40% of all COPD patients exhibit Type 2 inflammation, which is characterized by elevated BEC. This eosinophilic phenotype is associated with an increased risk of exacerbations and a favorable response to inhaled corticosteroids (ICS) as well as biologic therapies. However, BEC is subject to significant fluctuations over time. How many measurements are needed to reliably identify patients with an eosinophilic phenotype?