Abstract: Objective To explore the value of serological indexes C-reactive protein(CRP), erythrocyte sedimentation rate(ESR), procalcitonin(PCT) , interleukin-6(IL-6) and D-dimer(D-D) in early prediction of sepsis secondary to acute osteoarticular infection(AOI)in children. 
Methods A total of 149 children with AOI were enrolled as AOI group. According to presence or absence of secondary sepsis, they were divided into general infection group(n=108) and sepsis group(n=41). In addition, 71 healthy children in the same period were selected as control group. CRP, ESR, PCT, IL-6 and D-D were measured in all patients. 
Results The levels of CRP, ESR, PCT, IL-6 and D-D in the AOI group were higher than those in the normal control group(P＜0.05), and the levels of CRP, ESR, PCT, IL-6 and D-D in the general infection group were lower than those in the sepsis group(P＜0.05). Multivariate logistic regression analysis showed that the increase of CRP, ESR, PCT, IL-6 and D-D was an independent risk factor for sepsis secondary to AOI(P＜0.05). The AUC of combined detection of the five indicators was greater than that of the single detection, and the sensitivity and specificity were higher, which were 95.43% and 94.53% respectively. 
Conclusion The levels of CRP, ESR, PCT, IL-6 and D-D were significantly higher in children with AOI. Combined detection of the five indicators have a higher value in prediction and early diagnosis of secondary sepsis.

Key words: sepsis, osteoarthritis, serological indexes