In a Patient with clinical signs of Asthma which of the following tests will confirm the diagnosis

Ans. is 'c' i.e., Diurnal variation in PEF > 20 Percent Diagnosis of Asthma require Demonstration of Airways obstruction Decrease in the ratio of FEVI/FVc Demonstration of acute reversibility of airflow Administer 2-4 puffs of quick acting bronchodilator e.g., albuterol and repreat spirometry 10-15 min An increase in FEV , of 12% or more accompanied by an absolute increase in FEV,of at least 20 ml Demonstration of Airway hyperresponsiveness in response to methacholine challenge test A bronchoprovocator (Methacholine) is administered hyperresponsiveness of the airway is demonstrated by reduction of FEV1 to 20% Increased Peak expiratory flow rate variabilities Demonstration of diurnal variation in PEF of more than 20% strongly suggests diagnosis of Asthma