Diagnostic Value Of C- Reactive Protein And Hematological Parameters In Neonatal Septicemia

Objective: To evaluate the diagnostic value of C-reactive protein and hematological parameters and in combination to formulate a guideline for the diagnosis of neonatal septicemia.Methods: A retrospective analysis from January 2008 to June 2009 in Neonatal Department of Children's Hospital of Chongqing Medical University. Newborns were classified as a septicemia (81 cases), clinical sepsis(61 cases) or not sepsis (172 cases), based on the results of cultures, clinical features and a set of investigations. White cell count(WBC),Platelet count(PLT),C-reactive protein (CRP) and immature neutrophils to total neutrophil count ratio (I/T ratio) were used for diagnosis of neonatal septicemia. The sensitivity, specificity, predictive values (PV) , likelihood ratio(LR) and accuracy of the individual tests and different tests combination was also calculated.Results:(1) The detection rate of neonatal septicemia is 25.7% (81/314); (2) CRP> 8mg/L differed significantly between a septicemia group and not sepsis group ( P=0.0000 ) ;PLT < or =100×109/L differed significantly between a septicemia group and not sepsis group(P =0.0000); I/T> or =0.14 differed significantly between a septicemia group and not sepsis group(P =0.003); WBC>25×109/L(≤3 d)or WBC>20×109/L(>3 d)or WBC<7×109/L differed significantly between a septicemia group and not sepsis group(P =0.027);(3) Area under the ROC curve was 0.655 for CRP, 0.536 for I/T, 0.530 for PLT, 0.488 for WBC;(4) For the cut-off value of CRP> 8mg/L , the test was found to have a sensitivity of 34.6%, specificity of 80.7%, PPV of 0.384, NPV of 0.780, LR(+) of 1.793, LR(-) of 0.810 and diagnostic accuracy of 0.668 for neonatal septicemia; For the cut-off value of I/T> or =0.16, sensitivity, specificity, PPV, NPV, LR(+), LR(-) and diagnostic accuracy were found to be 18.5%,85.8%,0.313,0.752,1.303,0.950,0.685, respectively; For the cut-off value of PLT25×109/L(≤3 d )or WBC>20×109/L(>3 d )or WBC<7×109/L, sensitivity, specificity, PPV, NPV, LR(+), LR(-) and diagnostic accuracy were found to be 21.8%,83.3%,0.333,0.663,0.736,1.305,0.939, respectively. (5) The combination of WBC>25×109/L(≤3d)or WBC>20×109/L(>3d)or WBC<7×109/L and CRP> 8mg/L had sensitivity, specificity, PPV, NPV, LR(+), LR(-) and accuracy of 12.8%,93.1%,0.50,0.74,1.855,0.937 and 0.723, respectively;The combination of WBC>25×109/L(≤3d)or WBC>20×109/L(>3d)or WBC<7×109/L and CRP> 8mg/L and PLT25×109/L(≤3d)or WBC>20×109/L(>3d)or WBC<7×109/L , I/T> or =0.16, PLT8mg/L;(3) Patients with two or more abnormal hematological were categorized as clinical sepsis.