Diagnostic value of neutrophil CD64 index combined with procalcitonin and hypersensitive C-reactive protein in neonatal intrauterine bacterial infection

Objective To investigate the diagnostic value of neutrophil CD64 index combined with procalcitonin (PCT) and hypersensitive C-reactive protein (hs-CRP) in neonatal intrauterine bacterial infection. Methods Total of 138 neonates with high risk factors of intrauterine bacterial infection in Department of Neonatology, Haikou Maternal and Child Health Hospital from August 2017 to August 2018 were selected, according to the infection outcomes, 138 neonates were divided into infection group (28 cases) and non-infection group (110 case), CD64 index of neutrophils was measured by flow cytometry, the levels of serum PCT and hs-CRP were detected by immunofluorescence assay. CD64 index, expressions of PCT and hs-CRP in neutrophils of the two groups were observed, respectively; the diagnostic value of combined detection for neonatal intrauterine bacterial infection was also analyzed by receiver operating characteristic curve (ROC curve). Results CD64 index [(0.89 ± 0.25)% ], PCT [(2.24 ± 0.53) ng/ml] and hs-CRP [(21.25 ± 2.37) mg/L] of neutrophils in the infection group were significantly higher than those in the non-infection group [CD64: (0.26 ± 0.08)%, PCT: (0.42 ± 0.09) ng/ml, hs-CRP: (6.37 ± 1.33) mg/L], with significant differences (t = 22.475, P < 0.001; t = 34.459, P < 0.001; t = 44.171, P < 0.001). ROC curve analysis showed that the area under CD64 index + PCT + hs-CRP combined detection curve was 0.897, with the sensitivity for 85.71%, specificity for 92.73%, accuracy for 91.30%, which were higher than that of the two indicators combined detection and single indicator detection, and the misdiagnosis rate of the three indicators combined detection was 7.27% and the missed diagnosis rate was 14.29%. Conclusions Neutrophil CD64 index and PCT could be taken as early diagnostic indexes for neonatal intrauterine bacterial infection, the combined detection of CD64 index, PCT, and hs-CRP could significantly improve the sensitivity, specificity and accuracy of diagnosis. Key words: Neutrophil CD64; Procalcitonin; High sensitivity C-reactive protein; Newborn; Intrauterine bacterial infection; Diagnostic value