Investigation on the value of procalcitonin in diagnosing lower respiratory tract infection in adult / 中华检验医学杂志

ABSTRACT

ObjectiveTo investigate the value of serum procalcitonin (PCT) in diagnosing lower respiratory tract infection (LRTI) in adult.MethodsIn 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.ResultsMean 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.