To investigate the diagnostic value of serum procalcitonin (PCT), C-reactive protein (CRP) and neutrophil CD64 index in early diagnosis of umbilical vein catheterization.

Total of 537 neonates with umbilical vein catheterization from March 2017 to June 2019 in the 404 Hospital of Mianyang were selected, including 51 cases with infection (infected group) and 486 cases without infection (non-infected group). The levels of serum PCT, CRP and neutrophil CD64 index between the two groups were compared, the correlation of each index was analyzed, and the value of each index in early diagnosis of neonatal infection were analyzed by ROC curve.

The incidence of infection for children was 9.50% (51/537). The levels of serum PCT, CRP and CD64 index of cases in infected group were significantly higher than those in non-infected group [(16.31 ± 5.21) vs. (2.54 ± 0.63), (12.31 ± 2.96) vs. (3.95 ± 1.20), (2.97 ± 0.47) vs. (2.10 ± 0.35), with significant differences (t = 30.904, 27.883, 13.822; all P < 0.001). There were positive correlations between serum PCT and CRP (r =-0.316, P = 0.009) and CD64 index (r = 0.293, P = 0.015); while CRP and CD64 index was positively correlated (r = 0.285、P = 0.018). The best Cut-off values for single index of serum PCT, CRP and CD64 were 7.28 ng/ml, 6.12 mg/L and 2.54, and the areas under the ROC curve were 0.831, 0.819 and 0.775, respectively. The area under the curve of PCT, CRP and CD64 index for combined diagnosis was 0.933.

Serum PCT, CRP and neutrophil CD64 index had good diagnostic value for early neonatal infection with umbilical vein catheterization, and the combination of three indexes could significantly improve the diagnostic effect of early infection in children.