OBJECTIVE To explore the diagnostic value of combined detection of droplet digital polymerase chain reaction(ddPCR),C-reactive protein(CRP),procalcitonin(PCT)and neutrophil-to-lymphocyte ratio(NLR)for bacterial bloodstream infections.METHODS Patients with suspected bloodstream infections admitted to Jiangbin Hospital of Guangxi Zhuang Autonomous Region from Jan.2023 to Jun.2024 were selected as the study subjects,with a total of 993 specimens from 543 patients included.Based on ddPCR and blood culture(BC)results,the pa-tients were divided into BC+and/or ddPCR+group(424 specimens)and ddPCR-/BC-group(569 specimens).The bacterial species detected by ddPCR were further classified into single infection group(258 speci-mens),mixed infection group(160 specimens)and ddPCR-group(575 specimens).The levels of CRP,PCT and NLR were compared among the groups.Receiver operating characteristic(ROC)curves were used to evaluate the diagnostic efficacy of ddPCR,CRP,PCT and NLR separately and in combination for bacterial bloodstream in-fections.RESULTS The levels of CRP,PCT and NLR in the BC+and/or ddPCR+group were 71.61(37.00,108.81)mg/L,1.74(0.47,7.93)ng/ml and 9.82(5.53,18.07),respectively,which were higher than those in the ddPCR-/BC-group(P＜0.001).I n the ddPCR mixed infection group,the levels of CRP and PCT were 88.02(42.90,112.39)mg/L and 2.83(0.89,12.35)ng/ml,respectively,which were higher than those in the single infection group(P＜0.05).The qualitative results of ddPCR were better at predicting bloodstream infec-tions(OR=15.279,95％CI:6.525～35.776,P＜0.001).According to ROC curve analysis,ddPCR had the lar-gest area under the curve(AUC)among the single detection indicator(0.759),followed by PCT(0.732).The AUC for the combination of ddPCR qualitative results with CRP,PCT and NLR was 0.830,indicating that the di-agnostic performance of the combined detection was better than that of any single indicator.CONCLUSIONS The combination of ddPCR with PCT,CRP and NLR can improve the accuracy of diagnosing bacterial bloodstream in-fections.Compared with BC,ddPCR has higher sensitivity and can quickly identify the types and concentrations of pathogens in bloodstream infections.

OBJECTIVE To explore the diagnostic value of combined detection of droplet digital polymerase chain reaction(ddPCR),C-reactive protein(CRP),procalcitonin(PCT)and neutrophil-to-lymphocyte ratio(NLR)for bacterial bloodstream infections.METHODS Patients with suspected bloodstream infections admitted to Jiangbin Hospital of Guangxi Zhuang Autonomous Region from Jan.2023 to Jun.2024 were selected as the study subjects,with a total of 993 specimens from 543 patients included.Based on ddPCR and blood culture(BC)results,the pa-tients were divided into BC+and/or ddPCR+group(424 specimens)and ddPCR-/BC-group(569 specimens).The bacterial species detected by ddPCR were further classified into single infection group(258 speci-mens),mixed infection group(160 specimens)and ddPCR-group(575 specimens).The levels of CRP,PCT and NLR were compared among the groups.Receiver operating characteristic(ROC)curves were used to evaluate the diagnostic efficacy of ddPCR,CRP,PCT and NLR separately and in combination for bacterial bloodstream in-fections.RESULTS The levels of CRP,PCT and NLR in the BC+and/or ddPCR+group were 71.61(37.00,108.81)mg/L,1.74(0.47,7.93)ng/ml and 9.82(5.53,18.07),respectively,which were higher than those in the ddPCR-/BC-group(P＜0.001).I n the ddPCR mixed infection group,the levels of CRP and PCT were 88.02(42.90,112.39)mg/L and 2.83(0.89,12.35)ng/ml,respectively,which were higher than those in the single infection group(P＜0.05).The qualitative results of ddPCR were better at predicting bloodstream infec-tions(OR=15.279,95％CI:6.525～35.776,P＜0.001).According to ROC curve analysis,ddPCR had the lar-gest area under the curve(AUC)among the single detection indicator(0.759),followed by PCT(0.732).The AUC for the combination of ddPCR qualitative results with CRP,PCT and NLR was 0.830,indicating that the di-agnostic performance of the combined detection was better than that of any single indicator.CONCLUSIONS The combination of ddPCR with PCT,CRP and NLR can improve the accuracy of diagnosing bacterial bloodstream in-fections.Compared with BC,ddPCR has higher sensitivity and can quickly identify the types and concentrations of pathogens in bloodstream infections.