血清降钙素原水平在血流感染中的临床价值

摘要

目的：探讨血清降钙素原（PCT）水平在血流感染患者中的临床价值。方法回顾性分析我院568例同时送检PCT检测和血培养的结果，其中有效研究对象538例；比较PCT水平与血培养结果的关系，同时比较PCT在革兰阴性菌、革兰阳性菌及真菌之间的差异；选取多次行PCT检测的血培养阳性患者，并依据3周内转归分为好转组、迁延组及死亡组，比较不同转归患者PCT差异。各组间PCT差异比较采用秩和检验；预后分析中采用Fisher’s精确概率法。结果血培养阳性患者PCT值[3．39（0．69~6．52）μg/L]明显高于血培养阴性患者[0．31（0．09~1．48）μg/L]，差异有统计学意义（P＜0．05）；G－菌、G+菌及真菌感染患者PCT分别为4．39（1．80~10．85）μg/L、1．98（0．42~4．05）μg/L及0．62（0．39~3．98）μg/L，差异有统计学意义（P＜0．05）；根据受试者工作特征曲线（ROC），PCT临界值设定为3．315μg/L时，区分G－菌与真菌血流感染的灵敏度为67．9%，特异度为75．0%；设定为4．1μg/L时，PCT区分G+菌与G－菌血流感染的灵敏度为57．7%，特异度为76．5%；46例多次PCT检测血培养阳性患者中，PCT呈下降趋势时患者预后较好。结论血清PCT水平的检测有助于快速排除和诊断血流感染，同时有助于区分G－菌、G+菌及真菌所致的感染；动态监测PCT变化趋势有助于患者预后的判断。%Objective To evaluate the clinical value of serum procalcitonin levels in bloodstream infection. Methods 568 pa-tients who had both PCT detection and blood culture were collected from our hospital,538 of them were involved in this study. The relationship between serum PCT level and blood culture result was investigated. The PCT levels in patients with gram-negative bacterial bloodstream infection,gram-positive bacterial bloodstream infection and fungal bloodstream infection were compared. The bloodstream infection patients who had several PCT detection results were divided into three groups:better group,delay group and death group according to the infection outcome in three weeks. PCT levels between the three groups were compared and the corre-lation with prognosis of bloodstream infection were analyzed. Rank sum test and Fisher ’s test were used to analyze PCT values and prognosis among all the groups. Results In patients with positive blood culture result,the median of PCT [3.39(0.69~6.52)μg/L] was significantly higher than that [0.31(0.09~1.48)μg/L] in patients with negative blood culture result(P<0.05). The median of PCT in gram-negative bacterial infection,gram-positive bacterial infection and fungal infection were 4.39 (1.80~10.85)μg/L,1.98(0. 42~4.05)μg/L and 0.62(0.39~3.98)μg/L respectively,the differences among them were statistically significant (P<0.05). According to receiver operating characteristic curve,if 3.315μg/L was taken as a critical value,the sensitivity of PCT in diagnosis of gram-negative bacterial infection and fungal infection was 67.9%,and the specificity was 75.0%. And if 4.1μg/L was taken as a critical value,the sensitivity of PCT in diagnosis of gram-negative bacterial infection and gram-positive bacterial infection was 57.7%,and the specificity was 76.5%. In the 46 patients who detected PCT repeatedly,the prognosis of whom with decreasing PCT level was better than the others. Conclusions Serum PCT level is proved to be an effective marker for rapid diagnosis of bloodstream infec-tion,and is valuable to discriminate gram-negative bacterial infection,gram-positive bacterial infection and fungal infection. Dy-namic monitoring of PCT level has a certain reference value for the prognosis of bloodstream infection patients.