BACKGROUND Late-onset bloodstream infection (LOBSI) is common in very preterm infants. Early and accurate diagnosis is crucial for prognosis and outcome. We aimed to analyze the accuracy of routinely used inflammatory biomarkers in the diagnosis of LOBSI as compared to uninfected controls. METHODS In this single-center, retrospective case-control study, interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) were routinely measured, when infection was clinically suspected. The definition of LOBSI was based on positive blood culture, clinical signs of infection, and onset more than 72 hours after birth. RESULTS Among 285 enrolled infants, 66 developed LOBSI. IL-6 was superior to other markers, and levels greater than 100 ng/L had a sensitivity of 94% and a specificity of 99% for the presence of LOBSI. Receiver operating characteristic curve of IL-6 had area under the curve of 0.988 (95% CI = 0.975-1.00, P < .001). The negative predictive value of IL-6, CRP, and PCT for optimal cutoff values was 99%, 95%, and 93%, respectively. The logistic regression model of IL-6 > 100 ng/L or CRP > 10 mg/L were successfully predicted LOBSI in 97.9% of cases. CONCLUSIONS The combination of IL-6 and CRP seems to have great potential in routine rapid diagnosis of LOBSI development. High negative predictive value of all tested markers could encourage the early discontinuation of antibiotic treatment.

中文翻译：

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C 反应蛋白、白细胞介素 6 和降钙素原在极早产儿迟发型血流感染诊断中的应用。


背景迟发性血流感染（LOBSI）在极早产儿中很常见。早期准确的诊断对于预后和结果至关重要。我们的目的是分析常规使用的炎症生物标志物在 LOBSI 诊断中与未感染对照相比的准确性。方法 在这项单中心、回顾性病例对照研究中，当临床怀疑感染时，常规检测白细胞介素 6 (IL-6)、降钙素原 (PCT) 和 C 反应蛋白 (CRP)。 LOBSI 的定义基于血培养阳性、感染的临床症状以及出生后 72 小时以上发病。结果 在 285 名入组婴儿中，66 名患有 LOBSI。 IL-6 优于其他标志物，水平大于 100 ng/L 时，对于 LOBSI 的存在，敏感性为 94%，特异性为 99%。 IL-6 的受试者工作特征曲线的曲线下面积为 0.988 (95% CI = 0.975-1.00, P < .001)。 IL-6、CRP 和 PCT 对最佳截止值的阴性预测值分别为 99%、95% 和 93%。 IL-6 > 100 ng/L或CRP > 10 mg/L的逻辑回归模型成功预测了97.9%的病例的LOBSI。结论 IL-6 和 CRP 联合应用似乎在 LOBSI 发展的常规快速诊断中具有巨大潜力。所有测试标记物的高阴性预测值可能会鼓励尽早停止抗生素治疗。