探讨降钙素原(PCT)检测在重症肺部感染诊断中的价值，为临床合理用药提供依据。

选择我院收治的住院患者共90例作为研究组，门诊健康体检的病例30例作为对照组。研究组分为四组：肺部感染合并血培养阳性组30例，单纯肺部细菌感染组30例，病毒性肺部感染组30例，门诊健康体检患者对照组30例。分别收集四个分组在入院时、治疗中第三日、第七日中PCT、CRP、WBC的检验结果，并采用SPSS 19.0数据库软件进行统计学分析。

(1)肺部感染合并血培养阳性组、单纯肺部细菌感染组与照组在PCT、CRP和WBC上差异有统计学意义(P<0.01)；(2)病毒感染组与对照组在PCT上差异无统计学意义(P>0.05)，在CRP和WBC上差异有统计学意义(P<0.01)；(3)肺部感染合并血培养阳性组与单纯肺部细菌感染组在PCT、WBC上差异有统计学意义(P<0.01)，在CRP上差异无统计学意义(P>0.05)；(4)对比三次采样PCT水平，PCT随着治疗过程及病情好转逐渐下降，组间差异性有统计学意义(P<0.01)。

PCT对细菌感染的严重程度有一定的影响，感染越重，PCT的水平越高，所反映的疾病越严重，因此PCT为细菌性肺部感染性疾病早期诊断的灵敏指标，对其病情判断、评价抗生素疗效及降阶梯治疗、评估预后有重要的临床意义。

To explore the role of procalcitonin (PCT) in the diagnosis of severe pulmonary infection in order to provide suggestions for rational drug uses.

A total of 90 hospitalized patients with severe pulmonary infection from our hospital were taken as the experimental group, and 30 healthy volunteers from the outpatient health examination were used as the control group. In the present study, the experimental group was divided into three subgroups according to the disease category: pulmonary infection combined with positive blood culture subgroup (positive group, n=30), simple bacterial pulmonary infection subgroup (bacterial group, n=30), and viral pulmonary infection subgroup (viral group, n=30). And the results of PCT, CRP and WBC of all the patients were collected and analyzed on the admitted day, 3 days of treatment, and 7 days of treatment, respectively. Statistical analyses were performed with SPSS software (Version 16.0, SPSS Inc, Chicago, IL).

Significant difference was found in the results of PCT, CRP and WBC between the positive group and the bacterial group and the control group (P<0.01). There was no significant difference in the results of PCT between the viral group and the control group (P>0.05), however, significant difference was found in the results of CRP and WBC between the two groups (P<0.01). Significant difference was found in the results of PCT and WBC between the positive group and the bacterial group (P<0.01), while no significant difference was found in the results of CRP between the two groups (P>0.05). The PCT values decreased gradually with the improvement of pulmonary infection, with statistical significant difference between the groups.

PCT is a sensitive indicator of the early diagnosis of bacterial infectious diseases in the lungs. It has great significance in judging the patient′s condition, evaluating the therapeutic effects of antibiotics and de-escalation therapy, and assessing the prognosis of the patient.