Abstract: Objective To explore the clinical features of leukemoid reaction (LR) in children and the key points of differentiation from leukemia.Methods The clinical data of 89 children with leukocyte ≥30×109/L admitted to the internal medicine ward of Hunan Children's Hospital in the past two years (LR group) were retrospectively analyzed,including 44 cases of leukemoid reaction and 45 cases of leukemia.Another 89 children with non-leukemoid reaction(leukocyte <30×109/L) admitted in the same period were selected as the control group(NLR group).The general data,laboratory examination,hospital stay,discharge diagnosis and other clinical data of LR group and control group were statistically analyzed.The difference in laboratory indexes between LR group and leukemia group was compared.Results Compared with the non-leukemoid reaction(NLR) group,the ≥30×109/L group had a higher proportion of fever patients,longer hospital stay,higher neutrophil ratio and higher positive rate of blood culture.Pneumonia was the main diagnosis in the LR group,and the incidence of lung consolidation was statistically different between the two groups(P<0.05).The LR group in bacteremia patients had a higher gram-positive infection rate.The proportion of patients with leukocyte count ≥50×109/L in leukemia group was significantly higher than that in LR group,and there were statistically significant differences in platelet count,C-reactive protein,uric acid and lactate dehydrogenase levels between leukemia group and LR group.Conclusion Children with LR usually have a clear etiology and are at high risk for pneumonia and lung consolidation.A combination of clinical features and laboratory indicators can help early identification of leukemia in patients with leukocytosis.

Key words:

Leukemioid reaction, Leukocytosis, Leukemia, Lung consolidation, Bacteremia