FCN3 and Behcet disease: Using the XGBoost‐based model, key biomarkers including F11, ITIH4, SERPINA3, APMAP, ORM1, LRG1, ITIH3, FN1, FGL1, FCN3, C1QA, C5, PLTP, TPM3, and IGKV3‐64D were identified as critical variables for BD diagnosis (Figure 2C,D).