LADS London Asthma Diagnostics Study, A pragmatic diagnostic accuracy study of a triple diagnostic approach and exploratory biomarkers in adult asthma diagnosis

Asthma diagnosis in adults often remains uncertain, even after standard breathing tests. This study will test whether combining three portable diagnostic devices—oscillometry, spirometry, and FeNO (exhaled nitric oxide)—can reliably confirm or rule out asthma in a single clinic visit. Currently, many patients with possible asthma undergo repeated appointments and inconclusive tests, delaying treatment or leading to incorrect diagnoses. The standard reference for diagnosis requires two respiratory specialists to review a patient’s full history and test results, which is time-consuming and resource-intensive. This study compares the accuracy of the triple-device approach against that expert judgement. If the triple approach proves accurate, it could transform asthma diagnosis in primary care and outpatient clinics. Patients would receive a clear answer sooner, reducing unnecessary referrals and freeing up specialist time. Portable devices also make testing feasible in community settings, not just hospital lung-function labs. The study does not explore new fundamental mechanisms of asthma; it is a pragmatic diagnostic accuracy trial focused on improving a routine clinical pathway. Success would mean faster, more accessible, and more confident diagnosis for the roughly five million people in the UK living with asthma.