title: [The changes and clinical implications of serum procalcitonin in acute exacerbations of chronic obstructive pulmonary disease].
abstract: OBJECTIVE
  To investigate the changes and clinical implications of serum procalcitonin (PCT) in acute exacerbations of chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  A total of 45 patients with an acute exacerbation of COPD were studied. On presentation, serum PCT concentrations were measured, and quantitative sputum culture was also performed. The patients were reevaluated when they had returned to their stable clinical state. Potentially pathogenic microorganism (PPM) was only regarded as significant if they reached a growth of >or= 10(7) CFU/ml, indicating the presence of bacterial exacerbation of COPD.
  
  
  RESULTS
  (1) On presentation, sputum samples from 21 (46.7%) patients yielded PPM. When reevaluated in stable clinical state, sputum samples from 9 (20%) patients had a positive PPM culture [2.8 x 10(6) (1.3 x 10(6), 1.9 x 10(7)) CFU/ml], but with a significantly lower bacterial load than on presentation [7.0 x 10(7) (4.5 x 10(7), 7.1 x 10(8)) CFU/ml, Z = -2.666, P = 0.008]. (2) The patients were classified into two groups: group A included patients with bacterial exacerbation of COPD (n = 15), group B included patients with nonbacterial exacerbation of COPD (n = 30). The levels of PCT for patients of group A [0.24 (0.17, 0.28) microg/L] were significantly higher than group B [0.13 (0.10, 0.18) microg/L, Z = -3.531, P = 0.000]. When they had returned to their stable state, the levels of PCT for patients of group A decreased to 0.12 (0.10, 0.14) microg/L, which was significantly lower than in exacerbation [0.24 (0.17, 0.28) microg/L, Z = -3.298, P = 0.001]; But compared with exacerbation [0.13 (0.10, 0.18) microg/L], the levels of PCT for patients of group B did not changed [0.13 (0.10, 0.15) microg/L, Z = -1.614, P = 0.107]. In the stable state, there were no differences in the PCT measurement between the two groups (Z = -0.382, P = 0.703).
  
  
  CONCLUSIONS
  In patients presented with an acute exacerbation of COPD, the elevation of serum PCT is associated with bacterial infection.
authors.affiliation: Department of Respiratory Medicine, Peking University Third Hospital, Beijing 100083, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Chang
authors.forename: Wan-zhen
authors.initials: WZ
authors.lastname: Yao
authors.forename: Ya-hong
authors.initials: YH
authors.lastname: Chen
authors.forename: Zhen-ying
authors.initials: ZY
authors.lastname: Liu
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Zhang
mesh_terms: D000368:Aged; D001424:Bacterial Infections; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000382:microbiology; D044967:Serum / Q000378:metabolism*
chemical_list: C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide