血清降钙素原检测对革兰阴性菌或革兰阳性菌血流感染的诊断价值

目的探讨血清降钙素原（PCT）水平对鉴别革兰阴性（G-）菌与革兰阳性（G＋）菌血流感染的临床价值。方法回顾性分析从2012年1月至2013年5月人院的血流感染患者，所有患者血培养为单一菌株且检测了血清PCT水平，同期血培养阴性的局部感染患者47例为对照组。比较PCT水平在G-菌、G＋菌血流感染患者之间的差异，同时根据受试者工作特征（ROC）曲线判断PCT的诊断效能。结果纳入血流感染患者166例，其中G-菌感染109例，G＋菌感染57例。G一菌组、G’菌组和对照组PCT水平中位数分别为12．72ng／mL、2．50ng／mL和0．22ng／mL，各组间PCT水平差异有统计学意义（P〈0．05）。根据ROC曲线，当PCT界值设定为4．82ng／mL时，血清PCT水平区分G-与G＋菌所致血流感染的灵敏度为80．0％，特异度为74．7％。结论血清PCT水平检测对鉴别G-菌与G＋菌引起的血流感染患者有一定的临床应用价值。当PCT〉4．82ng／mL时，G-菌感染可能性大。

Diagnostic Value of Serum Procalcitonin Measurement for Identification of Gram-negative and Gram-positive Bacterial Bloodstream Infections

Objective To investigate the clinical value of serum procalcitonin （PCT） levels for differentiating Gram-negative （ G- ） and Gram-positive （ G ＋ ） bacterial bloodstream infections. Methods The clinical data of 166 patients with bloodstream infections admitted between January 2012 and May 2013 who had a single strain infection in blood culture and PCT levels results were analyzed retrospectively. Meanwhile patients with local infection with negative blood cultures were recruited as control. The serum PCT levels were compared between the patients with G- and G ＋ bacteria bloodstream infection. The cut-off value of PCT was determined by receiver operating characteristic （ROC） curve analysis. Results In 166 patients with bloodstream infections, 109 cases were infected with G- bacteria,57 cases with G＋ bacteria Median levels of PCT were 12. 72 ng/mL,2. 50 ng/mL, and O. 22 ng/mL in the G- bacteria infection group, the G ＋ bacteria infection group, and the control group, respectively, with significant difference among three groups. According to ROC curve, PCT level at 4. 82 ng/mL could distinguish G - bacteria infection from G ＋ bacteria infection with a sensitivity of 80. 0% and a specificity of 74. 7%. Conclusions Serum PCT has diagnostic value in differentiating G- and G＋ bacteria bloodstream infections. The risk of G- bacteria bloodstream infection is increased when PCT is 〉 4. 82 ng/mL.