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Introduction There is an unmet need for a validated qualitative and quantitative tool to assess environmental exposures in patients with interstitial lung disease (ILD), particularly hypersensitivity pneumonitis (HP). This study aimed to develop and validate a comprehensive tool to systematically identify exposures in ILD patients across South Asia.Methods A systematic literature review identified exposures associated with ≥5 documented HP cases, which were evaluated through a two-round Delphi survey involving 39 pulmonologists from India, Sri Lanka, Pakistan, and Nepal. The preliminary questionnaire was pilot-tested (N=30) to ensure clarity and usability. Following refinement, the final questionnaire was prospectively validated in 202 ILD patients across six centres in India and Sri Lanka. Each patient underwent centralized, protocolized online multidisciplinary discussion. The questionnaire had a qualitative part and a quantitative score ranging from 0 to 14.Results The systematic review screened 5,170 records and included 407 studies, identifying 24 exposure categories. A 50-item Delphi survey achieved expert consensus (>70%) on 17 qualitative and 4 quantitative items. The questionnaire was translated into Hindi, Tamil, and Sinhala. In the derivation cohort (n=40), the HP-SAQE score was significantly higher in HP vs. non-HP patients (median: 11.0 vs. 8.5; p=0.0015). This finding was validated in a separate cohort (n=162; median: 10.0 vs. 2.5; p<0.001). ROC analysis showed good diagnostic performance (AUC: 0.79 derivation; 0.86 validation). In the derivation cohort, the exposure score demonstrated an AUC of 0.79, with a cutoff of ≥9 yielding 80% sensitivity, 50% specificity (Youden’s Index 0.30). A higher cutoff of ≥11 improved specificity to 90% with a moderate sensitivity of 55% (Youden’s Index 0.45). In the validation cohort, the AUC was 0.88, indicating excellent discriminative performance. A cutoff of ≥9 provided the optimal balance with 73% sensitivity, 81% specificity (Youden’s Index 0.54).Abstract P94 Figure 1Conclusion The HP-SAQE is the first regionally adapted, qualitative and quantitative exposure assessment tool for ILD patients, developed through systematic review, Delphi consensus, and multicentre prospective validation. Its high specificity and consistent centre-wise performance support its role in structured exposure assessment, particularly in resource-limited or high-burden settings. Lower score cutoffs may enhance its utility as a clinical screening tool.