Objective To investigate the clinical significance of neutrophil parameters Neut‐X and Neut‐Y in the diagnosis of blood stream infection(BSI) .Methods The data in106 patients with blood stream infection and 51 cases in the healthy control group were retrospectively analyzed .The results of WBC ,neutrophil percentage ,Neut‐X ,Neut‐Y and procaclitonin (PCT ) were compared .Results Neut‐X and Neut‐Y in the BSI group were 1 393 .5 ± 33 .4 and 416 .2 ± 30 .0 respectively ,which were signifi‐cantly higher than 1 371 .9 ± 32 .7 and 391 .7 ± 23 .7 in bacterial culture negative group and 1 347 .2 ± 26 .2 and 371 .9 ± 21 .5 in the healthy control group ,the differences were statistically significant (P<0 .05) .Neut‐X and Neut‐Y had good correlation with PCT . Neut‐X and Neut‐Y levels in the Gram‐negative bacterial group were higher than those in the Gram‐positive bacterial group .Conclu‐sion Neut‐X and Neut‐Y parameters in the patients with BSI are significantly increased and can be used as the assistant diagnosis parameters of blood stream infection .