SAA1 and eosinophilic granulomatosis with polyangiitis: 1. Four candidate biomarkers were identified. SAA1, FGA, and SAP were upregulated in EGPA (sensitivity 82.3%, specificity 100%), while CETP was downregulated in EGPA compared to asthma. 2. The combination of SAA1, FGA, and SAP had a sensitivity and specificity of 82.35 and 100%, respectively, as biomarkers for early diagnosis of EGPA. 3. The combination of SAA1, FGA, SAP, and CETP had a sensitivity and specificity of 78 and 100%, respectively, as biomarkers for differential diagnosis of asthma.