Abstract: Objective To evaluate the role of blood culture and procalcitonin(PCT) test in the diagnosis of blood stream infection with other sites of infections. Methods The patients who were with blood stream infection and other sites infections admitted to our hospital from January,2014 to December,2014 were enrolled into this study and their clinical data were retrospectively analyzed,while the patients without blood stream infection but with other sites infections were selected as the control group. Results PCT tests in the patients with blood stream infection and other sites infection were higher than that in the control group(P<0.001);PCT with G^- infection were higher than patients with G⁺ or fungal infection(P<0.05).According to the ROC curve,12.19 ng/ml was taken as critical value.The negative predictive value for PCT level above 12.19 ng/ml was the highest (88.38%),which can be used as the predictor of removing the false positive of the blood culture.The positive predictive value and specificity of blood culture(+) and PCT above 12.19 ng/ml were the highest(95.45%;98.16%).The sensitivity of blood culture(+) or PCT tests above 12.19 ng/ml was the highest(80.77%). Conclusion The combined PCT test and blood culture can be used in the diagnosis of blood stream infection with other sites infections,which can improve the false positive and false negative of the blood culture,and provide evidence for the clinical decision-making.