OBJECTIVETo investigate the value of combined determination of neutrophil CD64 and procalcitonin (PCT) in the early diagnosis of neonatal bacterial infection.

METHODSAccording to discharge diagnosis, 37 neonates with bacterial infection were divided into sepsis (n=15) and ordinary infection (non-sepsis) groups (n=22). Twenty-one neonates without infection who were hospitalized during the same period of time were enrolled as the control group. Venous blood samples were collected immediately after admission. Flow cytometry was used to measure the serum level of neutrophil CD64. Chemiluminescence and immune transmission turbidimetry were used to measure the serum levels of PCT and CRP respectively.

RESULTSThe sepsis group had higher serum levels of neutrophil CD64, PCT, and CRP than the control group (P<0.01), the ordinary infection group had a higher serum level of neutrophil CD64 than the control group (P<0.01), and the sepsis group had higher serum levels of PCT and CRP than the ordinary infection group (P<0.01). The areas under the ROC curve (AUC) of neutrophil CD64, PCT, and CRP in diagnosing bacterial infection were 0.818, 0.818, and 0.704 respectively, and the AUC of combined neutrophil CD64 and PCT was 0.926. A combination of neutrophil CD64 and PCT had a sensitivity of 97.29% and an accuracy of 89.65% in the early diagnosis of neonatal bacterial infection.The sensitivity and accuracy were higher than those of a combination of CRP and neutrophil CD64 or PCT as well as neutrophil CD64, PCT, or CRP alone for the early diagnosis of neonatal bacterial infection.

CONCLUSIONSThe combined determination of neutrophil CD64 and PCT can improve the sensitivity and accuracy in the diagnosis of neonatal bacterial infection, which helps with early identification of bacterial infection.