Objective To explore the application value of serum procalcitonin(PCT)quantitative detection in diagnosing pediat-ric bloodstream infection.Methods The results of 183 cases of blood culture and simultaneous PCT detection in a hospital from February to November 2013 were analyzed retrospectively.The patients were divided into the non-bloodstream infection group and the bloodstream infection group according to the blood culture results as the golden standard.The differences of serum PCT concen-tration were compared between the two groups by the Mann-Whitney U test.Results The serum PCT concentration was 0.15 (0.065-0.55)ng/mL in the non-bloodstream infection group and 1.11(0.505-8.975)ng/mL in the bloodstream infection group, the difference was statistically significant(P =0.000);with 0.50ng/mL as the cut-off value of diagnosis,the sensitivity and the spe-cificity of PCT was 77.8% and 73.3% respectively,the positive and pegative predictive value of PCT was 24.1% and 96.8% re-spectively.Conclusion The quantitative detection of PCT can assist in rapidly diagnosing or excluding bloodstream infection and provides reference for avoiding the overuse of antibiotics or conducting the early anti-infection therapy.