Methacholine pre-test asthma probability score in paediatric population

<bold>Background:</bold> Methacholine challenge test (MCT) is a tool used to diagnose airway hyperresponsiveness in asthma. MCT interpretation relies on the patient's pretest asthma probability and the provocative dose(PD20). Yet there is no standardized method for approximating the pre-test probability, which is a challenge in the interpretation process. <bold>Objectives</bold>: Main objective: to standardize a symptom-based pre-test probability score in children referred for a MCT. Secondary objective: to assess the inter-investigator variability of the pre-test probability of asthma. <bold>Methods:</bold> We sent a 10-item medical history and symptoms questionnaire to 42 members of the French Paediatric Lung Function (LF) group and to colleagues abroad engaged in paediatric LF. We used Delphi methodology to guide item selection. In addition, 4 clinical cases were evaluated for pre-test asthma probability. <bold>Results:</bold> We received 23, 20, and 18 responses for the first, second, and third rounds, respectively. Based on these responses, one item was rejected and one was added resulting in a 10-item score that included child and their family's atopic status, the number, type, timing (night or early morning) of respiratory symptoms, their triggers, if any, history of early age (<3years) or recent (within the last 3 years) wheezing, and the effect of anti-asthmatic treatment on symptoms. Responder's pre-test asthma probability (0 to 1) varied across 4 clinical cases as shown in table 1. <bold>Conclusion</bold>: We found essential information for standardizing pre-test asthma probability before MCT in children. The scoring system needs validation against MCT results and final diagnosis. <table-wrap><object-id>erj;64/suppl_68/PA1345/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td></td><td>0-0.35</td><td>0.35-0.65</td><td>0.65-1</td></tr><tr><td>case 1</td><td>7</td><td>9</td><td>5</td></tr><tr><td>case 2</td><td>1</td><td>4</td><td>16</td></tr><tr><td>case 3</td><td>3</td><td>10</td><td>8</td></tr><tr><td>case 4</td><td>16</td><td>5</td><td>0</td></tr></tbody></table></table-wrap>