Objective To explore the differences in the effectiveness of using different blood indicators individually,in combination,and for dynamic monitoring in the diagnosis,differential diagnosis,and prognosis of bacterial infections.Methods 1843 cases with infectious symptoms or signs from January 2015 to September 2022 at the People's Hospital of Yuxi City were selected as the case group,and 2298 uninfected individuals during the same period were selected as the control group.Blood indicators of the two groups were collected.Variables were grouped according to gender,age group,specimen type,etc.SPSS 24.0 and Medcalc 20.0 were used for statistical analysis.Results The individual diagnostic efficacy of various blood indicators for detecting infection ranges from 0.656 to 0.937.When used together,the efficacy ranges from 0.907 to 0.987.The efficacy of distinguishing between G+c and G-b in different specimens is as follows:when PCT is used alone in blood,the AUC is 0.875 for males and 0.769 for females.However,the individual diagnostic efficacy in male mucous secretions,sterile body fluids,and non-adult male sputum is all≤0.7.Yet,when used together,the efficacy is AUC(0.789,0.737,0.86)respectively.The dynamic monitoring of PCT,IL-6,CRP,WBC,and LAC in adult patients at 24 h,48 h,and 72 h after admission shows statistically significant differences in prognostic efficacy for G+c and G-b(P<0.05).Conclusions Blood indicators have a certain diagnostic value for determining whether there is a bacterial infection,and there are gender differences.The combined use of these indicators is more effective.The diagnostic value of using blood indicators alone or in combination for distinguishing between G+c and G-b in different types of specimens varies.The use of PCT alone in blood specimens is the most effective.For adult males,the combined use of body surface mucous secretions and sterile body fluids is most effective,while for underage males,the combined use of sputum is most effective.The combined use for females is not effective.Dynamic monitoring of PCT,CRP,IL-6,LAC,and WBC has a high value for evaluating the prognosis and therapeutic effect of infections.The evaluation of G+c infection is most effective at 24 hours for IL-6,and for G-b infection,it is most effective at 72 hours for PCT.