title: Diagnostic accuracy of C-reactive protein and procalcitonin in the early detection of infection after elective colorectal surgery - a pilot study.
abstract: BACKGROUND
  Colorectal surgery is associated with postoperative infectious complications in up to 40% of cases, but the diagnosis of these complications is frequently misleading, delaying its resolution. Several biomarkers have been shown to be useful in infection diagnosis.
  
  
  METHODS
  We conducted a single-centre, prospective, observational study segregating patients submitted to elective colorectal surgery with primary anastomosis, CRP and PCT were measured daily. We compared infected and non-infected patients.
  
  
  RESULTS
  From October 2009 to June 2011, a total of 50 patients were included. Twenty-one patients developed infection. PCT and CRP before surgery were equally low in patients with or without postoperative infectious complications. After surgery, both PCT and CRP increased markedly. CRP time-course from the day of surgery onwards was significantly different in infected and non-infected patients (P = 0.001) whereas, PCT time-course was almost parallel in both groups (P = 0.866). Multiple comparisons between infected and non-infected patients from 5th to 9th postoperative days (POD) were performed and CRP concentration was significantly different (P < 0.01, Bonferroni correction), on the 6th, 7th and 8th POD. A CRP concentration > 5.0 mg/dl at the D6 was predictive of infection with a sensitivity of 85% and a specificity of 62% (positive likelihood ratio 2.2, negative likelihood ratio 0.2).
  
  
  CONCLUSIONS
  After a major elective surgical insult both CRP and PCT serum levels increased independently of the presence of infection. Besides serum CRP time-course showed to be useful in the early detection of an infectious complication whereas PCT was unhelpful.
authors.affiliation: Polyvalent Intensive Care Unit, São Francisco Xavier Hospital, CHLO, Lisbon, Portugal. joanapsilvestre@gmail.com.
authors.forename: Joana
authors.initials: J
authors.lastname: Silvestre
authors.forename: Jorge
authors.initials: J
authors.lastname: Rebanda
authors.forename: Carlos
authors.initials: C
authors.lastname: Lourenço
authors.forename: Pedro
authors.initials: P
authors.lastname: Póvoa
mesh_terms: D000328:Adult; D000368:Aged; D000714:Anastomosis, Surgical; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000737:chemistry*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D003107:Colorectal Surgery / Q000009:adverse effects*; D003141:Communicable Diseases / Q000175:diagnosis*; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide