@article{3000002, title = "Development and validation of the Food Allergy Severity Score", author = "Fernández-Rivas, M. and Gómez García, I. and Gonzalo-Fernández, A. and Fuentes Ferrer, M. and Dölle-Bierke, S. and Marco-Martín, G. and Ballmer-Weber, B.K. and Asero, R. and Belohlavkova, S. and Beyer, K. and de Blay, F. and Clausen, M. and Datema, M.R. and Dubakiene, R. and Grimshaw, K.E.C. and Hoffmann-Sommergruber, K. and Hourihane, J.O.B. and Jedrzejczak-Czechowicz, M. and Knulst, A.C. and Kralimarkova, T. and Le, T.-M. and Papadopoulos, N.G. and Popov, T.A. and Poulsen, L.K. and Purohit, A. and Seneviratne, S.L. and Simpson, A. and Sinaniotis, A. and Turkalji, M. and Vázquez-Cortés, S. and Vera-Berrios, R.N. and Muraro, A. and Worm, M. and Roberts, G. and van Ree, R. and Fernández-Pérez, C. and Turner, P.J. and Mills, E.N.C.", journal = "Allergy: European Journal of Allergy and Clinical Immunology", year = "2021", publisher = "John Wiley and Sons Inc", doi = "10.1111/all.15165", abstract = "Background: The heterogeneity and lack of validation of existing severity scores for food allergic reactions limit standardization of case management and research advances. We aimed to develop and validate a severity score for food allergic reactions. Methods: Following a multidisciplinary experts consensus, it was decided to develop a food allergy severity score (FASS) with ordinal (oFASS) and numerical (nFASS) formats. oFASS with 3 and 5 grades were generated through expert consensus, and nFASS by mathematical modeling. Evaluation was performed in the EuroPrevall outpatient clinic cohort (8232 food reactions) by logistic regression with request of emergency care and medications used as outcomes. Discrimination, classification, and calibration were calculated. Bootstrapping internal validation was followed by external validation (logistic regression) in 5 cohorts (3622 food reactions). Correlation of nFASS with the severity classification done by expert allergy clinicians by Best-Worst Scaling of 32 food reactions was calculated. Results: oFASS and nFASS map consistently, with nFASS having greater granularity. With the outcomes emergency care, adrenaline and critical medical treatment, oFASS and nFASS had a good discrimination (receiver operating characteristic area under the curve [ROC-AUC]>0.80), classification (sensitivity 0.87–0.92, specificity 0.73–0.78), and calibration. Bootstrapping over ROC-AUC showed negligible biases (1.0 × 10−6–1.23 × 10−3). In external validation, nFASS performed best with higher ROC-AUC. nFASS was strongly correlated (R 0.89) to best-worst scoring of 334 expert clinicians. Conclusion: FASS is a validated and reliable method to measure severity of food allergic reactions. The ordinal and numerical versions that map onto each other are suitable for use by different stakeholders in different settings. © 2021 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd." }