title: Immature platelet fraction in septic patients: clinical relevance of immature platelet fraction is limited to the sensitive and accurate discrimination of septic patients from non-septic patients, not to the discrimination of sepsis severity.
abstract: BACKGROUND
  The immature platelet fraction (IPF) reflects the degree of reticulated platelets. We evaluated performances of IPF as a biomarker for the discrimination of septic patients from non-septic patients and sepsis severity.
  
  
  METHODS
  Total 312 patients admitted between March and July 2013 were enrolled and samples were obtained at admission. Lactate (LA), procalcitonin (PCT), C-reactive protein (CRP), immature granulocyte fraction (IG), immature reticulocyte fraction (IRF), and IPF were analyzed as sepsis biomarkers and their performances were compared.
  
  
  RESULTS
  The performance of IPF (area under the curve [AUC]=0.868) in the discrimination of septic patients from non-septic patients was comparable to PCT/CRP/LA/IG (AUC=0.923/0.940/0.781/0.812, P=0.233/0.106/0.186/0.353, respectively), and was significantly better than the IRF (AUC=0.658, P=0.007). Sensitivity (89.8%, 95% confidence interval [CI] 84.9-99.8%) and accuracy (83.2%, 95% CI 78.8-90.0%) of IPF were the best among all biomarkers. The performance of IPF in discriminating septic patients from non-septic patients with local infection showed similar results. However, the IPF could not efficiently discriminate sepsis severity (AUC=0.599), similar to other biomarkers (AUC=0.519-0.752).
  
  
  CONCLUSIONS
  The IPF possessed high sensitivity/accuracy in discriminating septic patients from non-septic patients, regardless of local infection status. However, the IPF did not efficiently discriminate sepsis severity. The clinical relevance of IPF as a sepsis biomarker is, therefore, limited to sensitive and accurate discrimination of septic patients from non-septic patients, not discrimination of sepsis severity.
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.|Department of Laboratory Medicine, Pusan National University School of Medicine, Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.|Department of Emergency Medicine, Hallym University Medical Center, Anyang, Korea.
authors.forename: Sang Ook
authors.initials: SO
authors.lastname: Ha
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Young Uk
authors.initials: YU
authors.lastname: Cho
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Chan Jeoung
authors.initials: CJ
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea. ssjang@amc.seoul.kr.
authors.forename: Seongsoo
authors.initials: S
authors.lastname: Jang
authors.affiliation: Department of Pulmonology and Critical Care Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea. sbhong@amc.seoul.kr.
authors.forename: Sang Bum
authors.initials: SB
authors.lastname: Hong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001792:Blood Platelets / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012156:Reticulocytes / Q000473:pathology; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Biomarker; Discrimination; Immature platelet fraction; Sepsis; Severity