Diagnostic criteria for bronchial asthma is bronchospasm which is reversible with 2 puffs of beta adrenergic agonist with increase in FEV1 by at least
**Core Concept**
Bronchial asthma is characterized by chronic inflammation of the airways, leading to reversible airflow limitation. The diagnostic criteria for bronchial asthma involve demonstrating reversible airway obstruction, typically assessed using spirometry.
**Why the Correct Answer is Right**
The increase in FEV1 (forced expiratory volume in 1 second) after administration of a bronchodilator, such as a beta adrenergic agonist, is a key diagnostic criterion for bronchial asthma. A reversible increase in FEV1 of at least 12% and 200 mL above the baseline value is typically considered significant, indicating successful bronchodilation. This response is thought to result from the relaxation of airway smooth muscle, allowing for improved airflow.
**Why Each Wrong Option is Incorrect**
**Option A:** This value is too low and is not a commonly accepted threshold for bronchodilator responsiveness.
**Option B:** This value is not specified in the context of bronchodilator responsiveness for asthma diagnosis.
**Option C:** This value is too high and is not a commonly accepted threshold for bronchodilator responsiveness.
**Clinical Pearl / High-Yield Fact**
When interpreting spirometry results, remember that a 12% and 200 mL increase in FEV1 after bronchodilator administration is generally considered a significant response, indicating reversible airway obstruction.
**Correct Answer:** D.