目的 探讨降钙素原（Procalcitonin，PCT）水平与感染部位及致病微生物之间的相关性。 方法 采用回顾性研究方法，入选120例从2012年8月至2014年8月入住SICU的脓毒血症患者（年龄20-85岁），早晨采集血标本检测PCT；并进行血培养，痰培养、尿培养确定致病微生物。 结果 无明确感染源脓毒症患者平均PCT水平3.79；肺炎患者平均PCT水平24.87（P =0.038），尿路感染患者平均PCT水平52.19（P =0.0009），血源性感染患者平均PCT水平27.73（P = 0.0052）；革兰氏阳脓毒症患者平均PCT水平25.87（P= 0.0161），革兰阴性脓毒症患者平均PCT水平33.44（P = 0.0203），伴有真菌感染患者的PCT平均水平45.13（P = 0.0017）。 结论 不同的感染类型和致病微生物的PCT水平有明显差异，PCT水平可能预测不同的感染类型及致病微生物，可作为指导脓毒症患者诊断和治疗的指标之一。

Objective To investigate the correlation between procalcitonin (PCT) levels and the infection site/pathogenic microorganisms. Method 120 patients aged 20 to 85 years who were admitted to the surgery intensive care unit (SICU) from August 2012 to August 2014, who had a procalcitonin drawn were evaluated. PCT blood specimens were collected at morning in SICU; blood cultures data, sputum culture data, urine culture data were studied to determine the causative organism. Result 120 patient records were reviewed. Patients without a known infection/source of sepsis had a mean procalcitonin of 3.79. Those with pneumonia had a procalcitonin of 24.87 (p=0.038). Those with a UTI had a mean procalcitonin of 52.19（P=0.0009）. Patients with a bloodstream infection had a mean procalcitonin of 27.73(p=0.0052). Those with Gram-positive sepsis had a procalcitonin of 25.87 (p=0.0161) and those with Gram-negative sepsis at 45.13 (p= 0.0203). Those with fungal in-fections had a procalcitonin of 45.13 (p=0.0017). Conclusion PCT levels were significantly different in different types of infections and pathogenic microorganisms so that procalcitoninmay play a role in guiding treatment for Pyemiaby indicating causative organism and infection type.