降钙素原对成人下呼吸道感染诊断价值的研究

目的 评价降钙素原在成人下呼吸道感染中的诊断价值.方法 收集2008年7-12月北京大学人民医院的疑似下呼吸道感染的成人患者97例,分为下呼吸道感染合并脓毒症组、医院获得性肺炎组、社区获得性肺炎组、慢性阻塞性肺病急性加重组、其他下呼吸道感染组以及非感染性疾病组.记录各组患者的外周血血常规、红细胞沉降率、C反应蛋白、降钙素原、痰细菌培养、血培养等资料,所有病例均进行APACHEⅡ评分.降钙素原的检测采用荧光免疫夹心法.结果 下呼吸道感染合并脓毒症组、医院获得性肺炎组、社区获得性肺炎组、慢性阻塞性肺病急性加重组、其他下呼吸道感染组、非感染性疾病组降钙素原水平分别为10.1(0.7 ～37.0)、0.3(0.1 ～0.8)、0.2(0.1 ～0.9)、0.2(0.1～0.4)、0.3(0.1 ～0.5)、0.1(0.1 ～0.2)mg/L,差异有统计学意义(H=19.898,P＜0.01)；两两比较显示,下呼吸道感染合并脓毒症组、医院获得性肺炎组、社区获得性肺炎组、其他下呼吸道感染组降钙素原水平均高于非感染性疾病组(U值分别为0、18.000、81.000、20.000,P值均＜0.01)；且下呼吸道感染合并脓毒症组降钙素原水平显著高于其余感染组(U值分别为11.000、45.000、3.000、4.500,P均＜0.01).对细菌培养阳性患者的降钙素原和APACHEⅡ评分进行Pearson相关分析,r为0.499.取0.5 mg/L为临界值,降钙素原诊断下呼吸道感染的敏感度为32.6％,特异度为100％；而临界值为0.235 mg/L时,敏感度为53.9％,特异度为100％,诊断正确率为53.9％.结论 降钙素原在成人下呼吸道感染的诊断中具有一定价值,尤其是合并脓毒症时.适当下调降钙素原临界值可以进一步提高其诊断敏感度.

Investigation on the value of procalcitonin in diagnosing lower respiratory tract infection in adult

Objective To investigate the value of serum procalcitonin (PCT) in diagnosing lower respiratory tract infection (LRTI) in adult.Methods In a retrospective study,97 patients were enrolled,who admitted into Peking University People's Hospital with suspected LRTI from July to December 2008.During analysis,the subjects are categorized into groups of LRTI with sepsis,hospital-acquired pneumonia(HAP),community-acquired pneumonia(CAP),acute exacerbation of chronic obstructive lung disease (AECOPD),other LRTI and non-infectious diseases.In these cases,the following parameters were assessed regularly,such as white blood cell count,erythrocyte sedimentation rate( ESR),C-reactive protein (CRP),PCT,bacterial culture of both sputum and blood,and Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ score.PCT levels were determined using antibody-coated tubes as a complete diagnostic-kit (LUMI test Pro-Calcitonin) in a Luminometer.Results Mean PCT levels in groups of LRTI with sepsis, hospital-acquired pneumonia ( HAP ), community-acquired pneumonia ( CAP ), acute exacerbation of chronic obstructive lung disease( AECOPD),other LRTI,non-infectious diseases were 10.1 (0.7 -37.0),0.3(0.1 -0.8),0.2(0.1 -0.9),0.2(0.1 -0.4),0.3(0.1 -0.5),0.1 (0.1 -0.2) mg/L,respectively.There were statistical differences between these groups (H =19.898,P ＜ 0.01 ).And the PCT levels in groups of LRTI with sepsis,HAP,CAP,AECOPD,other LRTI were higher than group of non-infectious diseases ( U values were 0,18.000,81.000,20.000,all P ＜ 0.01 ).Patients with sepsis exhibited strongly higher PCT levels than patients with other lung diseases ( U values were 11.000,45.000,3.000,4.500,all P ＜ 0.01 ).Pearson correlation analysis of PCT levels with positive bacterial cultures and APACHE Ⅱ score was performed ( r =0.449).ROC analysis revealed that optimal discrimination between LRTI and non-infectious diseases could be performed at the cut-off point of 0.5 mg/L with a sensitivity of 32.6％ and specificity of 100％,while at a suggested cut-off point of 0.235 mg/L with a sensitivity of 53.9％ and specificity of 100％.Conclusions PCT is a more useful parameter for diagnosing lower respiratory tract infections( especially for those with sepsis) than other infectious markers such as CRP,ESR and white blood cell count.The sensitivity of PCT could be elevated with a reduction of the cut-off level.