Fig. 3.

The spearman correlation analysis between diseased severity and serum levels of YKL-40. a. The spearman correlation between severity and serum levels in all child pneumonia patients. No significant correlation was observed (spearman r = 0.066, P = 0.28). b. The correlation between severity and serum levels in children patients with bacterial infection (spearman r = 0.16, P = 0.09). c. The correlation between severity and serum levels in sole viral pneumonia patients (spearman r = − 0.19, P = 0.12). No significant correlation between admission levels and severity in all children with viral or bacterial pneumonia. X axis represents the severity of childhood pneumonia. Non-severe pneumonia = 1, severe pneumonia = 2, very severe pneumonia = 3