降钙素原和C-反应蛋白对儿童全身和局部细菌感染的诊断价值

目的 探讨降钙素原（PCT）和C-反应蛋白（CRP）对诊断全身和局部细菌感染的价值。方法 检索2011年1月至2012年6月在深圳市儿童医院住院病史系统中感染性疾病患儿的资料，分为全身细菌感染组（血培养阳性的严重脓毒症和败血症），局部细菌感染组（急性化脓性扁桃体炎、泌尿系感染及化脓性骨关节炎），病毒感染组（传染性单核细胞增多症和手足口病）。比较各组PCT、CRP水平和阳性率的差异。绘制受试者工作曲线（ROC）,计算曲线下面积（AUC）,评估PCT和CRP对全身和局部细菌感染的诊断价值。结果 148例患儿进入分析，全身细菌感染组19例，局部细菌感染组55例，病毒感染组74例。①CRP水平(mg·L-1)、PCT水平(μg·L-1)和PCT阳性率局部细菌感染组低于全身细菌感染组（CRP：21.35 vs 76.0，P＝0.001；PCT:0.10 vs 28.09, 32.7% vs 100%，P均<0.001）;CRP水平和阳性率局部细菌感染组高于病毒感染组（21.35 vs 4.0, 73.1% vs 27.0%, P均<0.001), PCT水平和阳性率局部细菌感染组与病毒感染组差异无统计学意义。3组WBC计数差异无统计学意义；WBC阳性率全身细菌感染组高于病毒感染组（84.5% vs 54.0%，P=0.017），局部细菌感染组与全身细菌感染组、病毒感染组差异无统计学意义。②PCT水平和阳性率局部细菌感染合并全身炎症反应综合征（SIRS）患儿显著高于不合并SIRS者（0.40 vs 0.08，P＝0.002；60.0% vs 17.1%, P＝0.001）,CRP水平和阳性率无显著差异。③PCT和CRP诊断全身细菌感染的ROC AUC分别为0.99和0.84；诊断局部细菌感染的ROC AUC分别为0.54和0.78。结论 PCT是识别全身细菌感染和监测局部细菌感染进展而合并SIRS的敏感指标。鉴别局部细菌感染时，CRP较PCT敏感。

Diagnostic value of procalcitonin and C-reactive protein as markers of systemic and localized bacterial infections

Objective To investigate procalcitonin（PCT）and CRP as markers of systemic and localized bacterial infections. Methods The cases of infectious diseases were recruited retrospectively in a children' hospital. Severe sepsis, septicemia with positive blood culture were recruited as systemic bacterial infection group. Acute suppurative tonsillitis, urinary tract infection and pyogenic osteomyelitis and septic arthritis were recruited as localized bacterial infection group. Infectious mononucleosis, hand foot and mouth disease were recruited as viral infection group. The value and positive rates of serum PCT and CRP among these groups were compared. The receiver operator characteristic curve (ROC) was drawn for PCT and CRP to diagnose systemic and localized bacterial infections, and the sensitivity and specificity were evaluated and the area under roc curve (AUC) and 95%CI were analyzed. Results One hundred and forty eight cases were recruited, 19 in systemic bacterial infection group, 55 in localized bacterial infections group and 74 in viral infection group. ①The levels of serum CRP and PCT and the positive rate of PCT were lower in localized bacterial infection group than in systemic bacterial infection group（CRP: 21.35 vs 76.0 mg·L-1, P=0.001; PCT:0.10 vs 28.09 μg·L-1, 32.7% vs 100%, P<0.001）. The levels of serum CRP and the positive rate were higher in localized bacterial infection group than in viral infection group（21.35 vs 4.0 mg·L-1, P<0.001; 73.1% vs 27.0%, P<0.001). The levels and the positive rate of serum CRP were not significantly different in these two groups. There were no significant differences of WBC in three groups. The positive rate of WBC was higher in systemic bacterial infection group than in viral infection group（84.5% vs 54.0%，P=0.017),but no significant difference was found between systemic bacterial infection group and localized bacterial infection group. There were no significant differences between localized bacterial infection group and viral infection group. ②In patients with localized bacterial infection, the level and the positive rate of serum PCT were higher in systemic inflammatory response syndrome (SIRS) group than non-SIRS group（0.40 vs 0.08, P =0.002; 60.0% vs 17.1%, P =0.001）, but there was no significant difference in the level and the positive rate of serum CRP between two groups. ③The AUC of ROC was 0.99 for PCT and 0.84 for CRP to diagnose systemic bacterial infection. It was 0.54 for PCT and 0.78 for CRP to diagnose localized bacterial infection, respectively. Conclusions In our study, PCT was identified as a sensitive marker of systemic bacterial infection and localized bacterial infections progressing into sepsis. As an indicator of bacterial infection, CRP was batter than PCT in localized infections.