Objective To explore the value of procalcitonin,C-reactive protein and neutrophil percentage in early diagnosis of bacterial bloodstream infection in patients with malignant tumor.Methods Retrospectively analyzed the clinical data of 413 cases with tumor fever who were performed PCT,CRP,blood test and blood culture in the same day in our hospital from January to December in 2015.According to blood culture results,they were divided into observation group(211 cases) and control group(202 cases).The observation group was divided into Gram-negative(G-) group and Gram-positive(G+) group.The diagnostic efficacy of PCT,CRP and NEUT％ on bacterial bloodstream infection was evaluated by receiver operating characteristic curve (ROC).Results The specificity of PCT in the observation group was the highest and the sensitivity of CRP was the highest.The levels of PCT,CRP and NEUT％ in the observation group were significantly higher than those in the control group(P＜0.05).PCT level in the G-group were apparently higher than that of G+ group(P＜0.05),while CRP and NEUT％ levels had no statistical significance between the two groups(P＞0.05).According to ROC curve,In the observation group,The AUC of PCT,CRP and NEUT％ were 0.848,0.796 and 0.718,respectively.In G-and G+ group,the AUC of PCT were 0.877 and 0.767,respectively.Conclusion PCT,CRP and NEUT％ were significantly increased in the malignant patient with bloodstream infection,PCT has showed better diagnostic efficiency compared to CRP or NEUT％ and better clinical value in distinguish between G-and G+ bacterial infection type.Combined detection of PCT,CRP,NEUT％ can help for early diagnosing malignant tumor with bacterial bloodstream infection.