Clinical value of blood related indexes in the diagnosis of bacterial infectious pneumonia in children

BACKGROUND: This study sought to explore the value of hematological indexes [i.e., the neutrophil count/lymphocyte count ratio (NLR), the platelet count/lymphocyte count ratio (PLR), and red cell distribution width (RDW) index] in the diagnosis of bacterial infectious pneumonia in children. METHODS: Fifty cases of mycoplasma infectious pneumonia, 50 cases of bacterial infectious pneumonia and 50 healthy children were enrolled in this study. The differences between the NLR, PLR, and RDW index values in each group were compared using the Mann-Whitney test. The correlation coefficients of the NLR, PLR, and RDW index with the interleukin-6 (IL-6) and procalcitonin (PCT) were analyzed using the Spearman’s rank test. The specificity and sensitivity of the NLR, PLR, and RDW index in the diagnosis of bacterial pneumonia in children were evaluated by receiver operating characteristic (ROC) curves. RESULTS: The NLR value of the children with bacterial infectious pneumonia was significantly higher than that of the children with mycoplasma infectious pneumonia (P<0.05) and healthy children (P<0.05), while the PLR value of the children with bacterial infectious pneumonia was significantly lower than that of the children with mycoplasma infectious pneumonia (P<0.05) and healthy children (P<0.05). There was no significant difference in the RDW index values of the healthy control children and the children with mycoplasma infectious pneumonia and bacterial infectious pneumonia (P>0.05). There was a positive correlation between NLR and serum IL-6 (R=0.203; P=0.041), and a negative correlation between PLR and serum PCT (R=–0.291; P=0.037). In addition, there was no significant correlation between the RDW index and serum IL-6, and the RDW index and serum PCT in children with bacterial infectious pneumonia. When the 3 indicators were each used to differentiate between healthy children and children with bacterial pneumonia, the area under the PLR curve was the largest for the ROC curve [0.898, 95% confidence interval (CI): 0.815–0.953]. In the differential diagnosis of mycoplasma pneumonia and bacterial pneumonia, the area under the PLR curve was also the largest (0.803, 95% CI: 0.577–0.780). CONCLUSIONS: The PLR has clinical value in the diagnosis of bacterial infectious pneumonia in children.