To describe the lung function questionnaire (LFQ) to identify airflow obstruction for patients with chronic obstructive pulmonary disease (COPD) along with spirometry tests. 200 COPD patients with age ≥40-year-old were studied in department of chest diseases in Bhaskar medical college. The accuracy of the final subset of LFQ items for identifying individuals with airflow obstruction (forced expiratory volume in one second / forced vital capacity <0.70) versus those without it. The model with all five items (age; smoking history; the presence of wheeze, dyspnea, and phlegm) compared with models with combinations of fewer LFQ items had the highest classification accuracy (area under the curve [AUC] = 0.72) with sensitivity and specificity of 73.1% and 58.1%, respectively. The presence of three or more factors yielded the highest AUC, a result suggesting that three or more affirmative answers is the most appropriate criterion indicating presence of airflow obstruction. The above five-item LFQ retained sufficient accurac
