MMP9 and syringocystadenoma papilliferum: The AUC of the two combined diagnosis of RP was 0.919, the AUC of serum MMP-9 and SAA in sCAP was 0.809 and 0.797, and the AUC of the two combined diagnosis of sCAP is 0.873, indicating that the two have a good diagnostic value for RP and sCAP, and the diagnosis of RP is better than sCAP.