Background The ratio of patients attending specialist occupational lung disease services who are confirmed to have an occupational lung disease is unknown.

Aim To determine the likelihood of occupational asthma or work related lung disease as a new referral in a specialist tertiary clinic.

Methods Patients seen in a tertiary clinic Jan 2016 to Dec 2016 were identified and case notes examined retrospectively for final diagnosis.

Results 481 patient attendances were identified of which 102 were new referrals. 41 of 102 (40%) were referred as possible work related interstitial lung disease or asbestos related lung disease. 13/41 (31.7%) were diagnosed asbestosis, 10 (24%) diffuse pleural thickening, 5 (12%) pleural plaques, 6 (14.6%) Usual Interstital Pneumonia (UIP) with asbestos exposure, 3 (7%) silicosis, 1 sarcoidosis and 3 unclear. 61 of 102 (60%) were referred with either possible work related airflow obstruction, asthma like symptoms at work or work related allergy symptoms. 16/61 (26%) were confirmed as occupational asthma due to a sensitising agent, 10 (16%) constitutional asthma, 20 (33%) no lung disease, 1 (1.6%) smoking related COPD, 5 (8%) inducible laryngeal obstruction, 2 anxiety, 1 (1.6%) Reactive Airways Dysfunction syndrome, 1 (1.6%) Byssinosis, 1 (1.6%) work related anaphylaxis, 1 (1.6%) work related urticaria. 3 had asthma but the cause remained unclear. 20/61 (33%) or 1 in 3 cases referred with possible work related airflow obstruction, asthma or allergy had a work related final diagnosis.

Conclusion The majority of cases seen are to determine causes of airflow obstruction/asthma like symptoms rather than interstitial lung disease in the tertiary setting. Most of these are found not to have asthma or a work related diagnosis. More cases of occupational asthma (16+1 cases) were identified in total than asbestosis (13 cases); however asbestos related pleural disease was frequently identified (15 cases), making asbestos related disease the most common occupational related lung diagnosis. The likelihood of diagnosing occupational asthma due to a sensitising agent in this tertiary setting is 1 in 4. 1 in 3 cases referred with possible interstitial lung disease had sufficient exposure and clinical/radiological evidence for a diagnosis of asbestosis, 1 in 14 (7%) had silicosis.