Due to lacking of specific clinical manifestations of early bacterial infection,the use of many antibacterial drugs without indications led to the emergence of drug-resistant strains. Bacterial culture is the gold standard for diagnosis of bacterial infection,but the detection is time-consuming and has many interference factors,so it cannot be used for early diagnosis. WBC( white blood cell),ESR( erythrocyte sedimentation rate) and CRP( C-reactive protein) are nonspecific index. Several studies have found t...