Positive Bronchial Challenge
Overview
Procedure
- Histamine or methacholine is given to stimulate bronchoconstriction
- FEV₁ is measured before and after the dose.
Significance
- Worsening FEV₁ after the stimulus is suggestive of asthma.
- The test has high negative predictive value, though the positive predictive value is poor as certain other respiratory conditions will result in false positive.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
