Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School, Norfolk, VA, USA.
Division of Pulmonary and Critical Care Medicine, Eastern Virginia Medical School, Norfolk, VA, USA.
J Crit Care. 2020 Dec;60:135-139. doi: 10.1016/j.jcrc.2020.07.026. Epub 2020 Aug 8.
The global burden of death due to sepsis is considerable. Early diagnosis is essential to improve the outcome of this deadly syndrome. Yet, the diagnosis of sepsis is fraught with difficulties. Patients with blood stream infection (BSI) are at an increased risk of complications and death. The aim of this study was to determine the diagnostic accuracy of four readily available biomarkers to diagnose BSI in patients with suspected sepsis.
In this retrospective, observational, Electronic Medical Record based study we compared the accuracy of procalcitonin (PCT), serum lactate concentration, total white blood cell (WBC) count and the neutrophil-lymphocyte count ratio (NLCR) to diagnose BSI in adult patients presenting to hospital with suspected sepsis. Based on the blood culture results patients were classified into 1 of the following 5 groups: i) negative blood cultures, ii) positive for a bacterial pathogen, iii) positive for a potential pathogen, iv) fungal pathogen and v) potential contaminant. Group 2 was further divided into Gram -ve and Gram +ve pathogens. Receiver operating characteristic (ROC) curves were constructed to compare the diagnostic performance of the biomarkers.
There were 1767 discreet patient admissions. The median PCT concentration differed significantly across blood culture groups (p < 0.0001). The highest median PCT concentration was observed in patients with a Gram-negative pathogen (17.1 ng/mL; IQR 3.6-49.7) and the lowest PCT in patients with negative blood cultures (0.6 ng/mL; IQR 0.2-2.8). The AUROC was 0.83 (0.79-0.86) for PCT, 0.68 (0.64-0.72) for the NLCR, 0.55 (0.51-0.60) for lactate concentration and 0.52 (0.48-0.57) for the WBC count. The AUROC for PCT was significantly greater than that of the NLCR (p < 0.0001). A PCT less than 0.5 ng/mL had a negative predictive value of 95% for excluding BSI. The best cut-off value of PCT for predicting BSI was 1.5 ng/ml.
Our results suggest that PCT of less than 0.5 ng/mL may be an effective screening tool to exclude BSI as the cause of sepsis, while the diagnosis of BSI should be considered in patients with a PCT above this threshold. The total WBC count and blood lactate concentration may not be reliable biomarkers for the diagnosis of BSI. The NLCR may be a useful screening test for BSI when PCT assays are not available.
全球因败血症导致的死亡负担相当大。早期诊断对于改善这种致命综合征的预后至关重要。然而，败血症的诊断充满了困难。患有血流感染（BSI）的患者有发生并发症和死亡的较高风险。本研究旨在确定四种现成的生物标志物在疑似败血症患者中诊断 BSI 的诊断准确性。
在这项回顾性、观察性、基于电子病历的研究中，我们比较了降钙素原（PCT）、血清乳酸浓度、总白细胞（WBC）计数和中性粒细胞-淋巴细胞计数比值（NLCR）在诊断疑似败血症的成年患者中诊断 BSI 的准确性。根据血培养结果，患者被分为以下 5 组之一：i）阴性血培养，ii）细菌病原体阳性，iii）潜在病原体阳性，iv）真菌病原体和 v）潜在污染物。组 2 进一步分为革兰氏阴性和革兰氏阳性病原体。构建了接收器工作特征（ROC）曲线来比较生物标志物的诊断性能。
共有 1767 名离散患者入院。血培养组之间的 PCT 浓度差异有统计学意义（p<0.0001）。革兰氏阴性病原体患者的 PCT 浓度最高（17.1ng/mL；IQR 3.6-49.7），阴性血培养患者的 PCT 浓度最低（0.6ng/mL；IQR 0.2-2.8）。PCT 的 AUROC 为 0.83（0.79-0.86），NLCR 为 0.68（0.64-0.72），乳酸浓度为 0.55（0.51-0.60），WBC 计数为 0.52（0.48-0.57）。PCT 的 AUROC 明显大于 NLCR（p<0.0001）。PCT 小于 0.5ng/mL 时，排除 BSI 的阴性预测值为 95%。预测 BSI 的最佳 PCT 截断值为 1.5ng/ml。
我们的结果表明，PCT 小于 0.5ng/mL 可能是一种有效的筛选工具，可排除 BSI 作为败血症的病因，而 PCT 高于此阈值的患者应考虑 BSI 的诊断。白细胞总数和血乳酸浓度可能不是诊断 BSI 的可靠生物标志物。当无法进行 PCT 检测时，NLCR 可能是 BSI 的有用筛选试验。
