BMC Infect Dis. 2013 Jun 15;13:272. doi: 10.1186/1471-2334-13-272.
Procalcitonin (PCT) is widely used in critically ill patients to diagnose clinically significant infection and sepsis. Aim of this study was to evaluate the prognostic value of PCT in comparison to white blood cell count (WBC) and C-reactive protein (CRP) for clinical outcome and its correlation with microbiological etiology in patients with infective endocarditis (IE).
A retrospective single-center analysis was performed from 2007 till 2009. All patients were diagnosed having IE according to Duke standard criteria. Before starting antibiotic therapy, WBC, CRP and PCT were measured and blood cultures were taken for microbiological diagnosis of the etiological pathogen. Patients were followed up during in-hospital stay for poor outcome, defined as death or serious complications due to IE.
During the study period 50 patients (57 ± 17 years, 72% male) fulfilling Duke criteria for IE were identified. In all patients PCT measurements before start of antibiotic therapy were available. In ROC analysis, a cut-off for PCT > 0.5 ng/mL was most accurate for the prediction of poor outcome with a sensitivity of 73% and specificity of 79%, a positive predictive value of 79% and a negative predictive value of 73%. Patients with a PCT > 0.5 ng/mL had an odds ratio of 12.8 (95% CI 2.5-66.2) for finding Staphylococcus aureus in blood cultures.
For the first time, this study shows that in IE, an initial value of PCT > 0.5 ng/mL is a useful predictor of poor outcome, i.e. death or serious infectious complications. PCT > 0.5 ng/mL should raise the suspicion of Staphylococcus aureus as the etiological pathogen, whereas PCT levels < 0.5 ng/mL make staphylococcal infection unlikely.
降钙素原（PCT）广泛用于重症患者，以诊断有临床意义的感染和败血症。本研究旨在评估 PCT 与白细胞计数（WBC）和 C 反应蛋白（CRP）相比，对感染性心内膜炎（IE）患者临床预后的预测价值，及其与微生物病因学的相关性。
这是一项回顾性单中心分析，时间为 2007 年至 2009 年。所有患者均根据 Duke 标准诊断为 IE。在开始抗生素治疗前，测量 WBC、CRP 和 PCT，并进行血培养以对病原体进行微生物学诊断。患者在住院期间进行随访，以评估不良预后，定义为因 IE 死亡或出现严重并发症。
在研究期间，符合 Duke 标准的 IE 患者共 50 例（57±17 岁，72%为男性）。所有患者在开始抗生素治疗前均有 PCT 测量值。在 ROC 分析中，PCT＞0.5ng/ml 对预测不良预后的准确性最高，敏感性为 73%，特异性为 79%，阳性预测值为 79%，阴性预测值为 73%。PCT＞0.5ng/ml 的患者血培养发现金黄色葡萄球菌的优势比为 12.8（95%CI 2.5-66.2）。
本研究首次表明，IE 患者初始 PCT 值＞0.5ng/ml 是不良预后（即死亡或严重感染并发症）的有用预测指标。PCT＞0.5ng/ml 应提示金黄色葡萄球菌为病原体，而 PCT 水平＜0.5ng/ml 则提示金黄色葡萄球菌感染的可能性较小。
