目的探讨血清降钙素原(PCT)检测在儿童下呼吸道感染病因学诊断中的价值。方法回顾性分析疑似下呼吸道感染的1 873例儿童患者送检的首次痰培养及PCT检测结果,比较患者痰培养结果与血清PCT水平的关系,分析革兰阴性菌、革兰阳性菌及真菌感染后患者体内PCT水平的差异。结果以0.5μg/L为血清PCT阳性阈值。痰培养病原菌阳性率为30.1%,血清PCT阳性率为35.6%。病原菌培养阳性患儿血清PCT检测值和PCT阳性率均明显高于细菌培养阴性患儿和正常菌群患儿,差异均有统计学意义(P<0.01);革兰阴性菌或革兰阳性菌单独感染、混合感染和真菌感染血清PCT阳性率差异无统计学意义(P>0.05)。结论血清PCT检测可作为呼吸道感染病因检测的重要指标,用于指导临床抗生素的使用。 Objective To investigate the value of serum procalcitonin (PCT) detection in the etiological diagnosis of children with lower respiratory tract infection. Methods The first sputum culture and PCT test results of 1873 pediatric patients with suspected lower respiratory tract infection were retrospectively analyzed. The relationship between sputum culture results and serum PCT levels was analyzed and Gram-negative bacteria, Gram-positive bacteria and fungal infections were analyzed Differences in PCT levels in post-patient patients. Results 0.5μg / L serum PCT positive threshold. The positive rate of sputum culture pathogen was 30.1% and the positive rate of serum PCT was 35.6%. The serum PCT detection value and PCT positive rate were significantly higher in children with positive culture of pathogen than in children with negative bacterial culture and normal flora, the difference was statistically significant (P <0.01); Gram-negative or Gram-positive bacteria There was no significant difference in the positive rate of PCT between the single infection, mixed infection and fungal infection (P> 0.05). Conclusion Serum PCT detection can be used as an important indicator of the detection of respiratory tract infection, used to guide the clinical use of antibiotics.