eCRS is linked with skewed T-helper two or immunoglobulin E (IgE)-mediated allergic responses, with differing diagnosis, prognosis, and management to non-eCRS.

The association between biomarkers and eCRS was investigated to assess the predictors of eCRS.

A cross-sectional study of adult patients with CRS undergoing endoscopic sinus surgery was conducted. eCRS was defined by histopathological assessment showing >10 eosinophils/high-power field on sinus mucosal biopsy. Comparisons between eCRS and non-eCRS patients were performed.

Three hundred forty-five patients were recruited, with 206 identified as eCRS, 41% with asthma, and 47% CRS with nasal polyps. eCRS patients were more likely to have asthma (P < .01) and nasal polyps. Blood eosinophils were significantly elevated in eCRS, as were eosinophils as a ratio of WCC. ESR was decreased when compared with non-eCRS. Receiver operating characteristic curve analysis predicted high tissue eosinophilia at blood eosinophil levels above 0.24 × 109/L. eCRS was expected at eosinophil above 4.27% of total WCC. There was no significant association among WCC, CRP, IgE, or ImmunoCAP testing.

The study concluded that eCRS is associated with elevated blood eosinophils, eosinophil ratio, and lower ESR compared with non-eCRS.