title: Comparison of serum procalcitonin in respiratory infections and bloodstream infections.
abstract: OBJECTIVE
  This study observed the relationship between procalcitonin (PCT) and results of sputum culture, the relationship between PCT and results of blood culture to evaluate and compare the value of PCT in respiratory and bloodstream infections.
  
  
  METHODS
  We analyzed 1616 patients in which PCT and sputum culture were concurrently ordered and analyzed, and 1096 patients in which PCT and blood culture were concurrently ordered and analyzed from January 2014 to May 2015. PCT concentrations were measured by on a Roche Cobas E601 ECL analyzer.
  
  
  RESULTS
  The average values of PCT from patients with sputum culture positive and negative were 0.42 (0.17-2.16) and 0.12 (0.06-0.57) ng/ml respectively, and the average values of PCT from patients with blood culture positive and negative were 9.54 (2.10-48.47) and 0.28 (0.10-1.23) ng/ml respectively. In sputum culture, positive rate of PCT in cases with growth of pathogens was 47.1%. In blood culture, positive rate of PCT in cases with growth of pathogens was 89.2%.
  
  
  CONCLUSIONS
  PCT is useful in early diagnosis of respiratory infections and bloodstream infections, but the specificity of PCT in diagnosing respiratory infections is not as high as it is in bloodstream infections.
authors.affiliation: Department of Laboratory Medicine, The People's Hospital of Guangxi Zhuang Autonomous Region Nanning 530021, China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Laboratory Medicine, The People's Hospital of Guangxi Zhuang Autonomous Region Nanning 530021, China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Department of Laboratory Medicine, The People's Hospital of Guangxi Zhuang Autonomous RegionNanning 530021, China; Department of Surgical Oncology, Roswell Park Cancer InstituteElm and Carlton Streets, Buffalo, New York 14263, USA.
authors.forename: Huayi
authors.initials: H
authors.lastname: Huang
keywords: Procalcitonin; blood culture; bloodstream infections; respiratory infections; sputum culture