Phase I: laboratory based study to develop LC-MS/MS assay of urine / blood to detect presence or lack asthma medication in 50 volunteers with asthma. Phase II: once the test is validated it will be tested in a 100 patients attending the asthma clinics to test its clinical utility. Urine and blood samples will be collected from patients at time of clinic attendance to test for asthma medication panel and outcome will determine adherence or non-adherence. Clinical outcomes of adherent versus non adherent groups will be compared in terms of asthma control, lung function, biomarkers FeNO and blood eosinophils, exacerbation frequency and hospitalisation.