OBJECTIVE To investigate the levels of procalcitonin (PCT), platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), white blood cell count (WBC) and serum amyloid A (SAA) in newborns with bloodstream infection, and their diagnostic value for early diagnosis of bloodstream infection in newborns.

METHODS A total of 100 neonates with positive blood culture results from Jan. 2021 to Jan. 2024 at Taizhou Hospital of Zhejiang Province were selected. These cases were divided into three groups based on the type of pathogen: 74 cases in the gram-negative bacterial group, 19 cases in the gram-positive bacterial group, and 7 cases in the fungal group. Additionally, 100 neonates with negative blood culture results during the same period were selected as the control group. By comparing the levels of PCT, PLR, NLR, WBC and SAA in the blood of newborns infected with different pathogens, the diagnostic value of various indicators on the receiver operating characteristic (ROC) curve for diagnosis of bloodstream infection in newborns was evaluated.

RESULTS Among 100 newborns with positive blood cultures, 74 strains of gram-negative bacteria, 19 strains of gram-positive bacteria, and 7 strains of fungi were identified. The levels of PCT, PLR, NLR, WBC and SAA in the gram-positive, gram-negative and fungal groups were all higher than those in the control group (P < 0.05). The ROC curve results showed that the diagnostic efficacy of the combination of PCT, PLR, NLR, WBC and SAA for gram-negative and gram-positive bloodstream infections was superior to that of each individual indicator(P < 0.05), with area under the curve (AUC) of 0.982 and 0.969, respectively.

CONCLUSION PCT, PLR, NLR, WBC and SAA can serve as effective biomarkers for the early diagnosis of bloodstream infection in newborns, aiding in the rapid and accurate identification of the type of infection.