<prompt> Ina patient with clinical signs of asthma which of the following tests will confirm the diagnosisIncrease in FEV1FVC200 ml increase in FEV1 after MethacholineDiurnal variation inPEF20Reduction of FEV120 after bronchodilators  <response>: Demonstrated outflow obstruction.,: Decreased FEV1 Decreased PEF Decreased FEV1FVC Ref Harrison 19th edition pg 1675 