Is bronchial provocation test positivity associated with blood eosinophil count and cut-off value?

Area of Science:

• Allergy and Immunology
• Respiratory Medicine
• Diagnostic Biomarkers

Background:

• Asthma involves airway hyperresponsiveness and chronic inflammation, with eosinophils playing a key role.
• Bronchial provocation tests (BPT) are used to assess airway hyperresponsiveness.
• The relationship between blood eosinophil counts and BPT outcomes requires further clarification.

Purpose of the Study:

• To investigate the association between BPT results and blood eosinophil counts in asthma patients.
• To determine a potential cut-off value for blood eosinophil count in relation to BPT positivity.

Main Methods:

• Retrospective analysis of 246 asthma patients undergoing methacholine BPT.
• Patients were categorized based on BPT positivity and negativity.
• Blood eosinophil counts were compared between BPT-positive and BPT-negative groups.

Main Results:

• BPT was positive in 36.6% of patients and negative in 63.4%.
• Blood eosinophil counts were significantly higher in BPT-positive patients (135 cells/µl) compared to BPT-negative patients (119 cells/µl).
• A blood eosinophil cut-off value of ≥226 cells/µl was identified, with 30.0% sensitivity and 87.7% specificity.

Conclusions:

• BPT positivity in asthma is associated with elevated blood eosinophil counts.
• The determined cut-off value of ≥226 cells/µl for blood eosinophil count may assist in BPT planning and asthma diagnosis.