29th January 2024

A 35-year-old woman presented to ED with a worsening history of shortness of breath on a background of allergic rhinitis and asthma.

A 35-year-old woman presented to ED with a worsening history of shortness of breath on a background of allergic rhinitis and asthma. His blood tests demonstrate an eosinophil level of 2.1×109/L and CRP of 54mg/L. CXR shows diffuse pulmonary infiltration. 

Which of these laboratory findings would most strongly support a diagnosis of eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)?