Laboratory Features of Trichinellosis and Eosinophilia Threshold for Testing, Nunavik, Quebec, Canada, 2009-2019

Prolonged eosinophilia is characteristic of trichinellosis. To determine the optimal eosinophil threshold for reflex Trichinella testing, we examined all 43 cases in Nunavik, Quebec, Canada, during 2009-2019. Using receiver operating characteristic analysis, we determined that eosinophil counts >0.8 × 10⁹ cells/L should prompt consideration of trichinellosis and testing to rapidly identify potential outbreaks.