title: Procalcitonin and interleukin 6 for predicting blood culture positivity in sepsis.
abstract: BACKGROUND
  Procalcitonin and interleukin 6 (IL-6) are well-known predictors of blood culture positivity in patients with sepsis. However, the association of procalcitonin and IL-6 with blood culture positivity was assessed separately in previous studies. This study aims to examine and compare the performance of procalcitonin and IL-6, measured concomitantly, in predicting blood culture positivity in patients with sepsis.
  
  
  METHODS
  Forty adult patients with sepsis were enrolled in the study. Blood cultures were drawn before the institution of antibiotic therapy. The area under the curve (AUC) of the receiver operating characteristic curve was estimated to assess the performance of procalcitonin and IL-6 in predicting blood culture positivity.
  
  
  RESULTS
  Positive blood cultures were detected in 10 patients (25%). The AUC of procalcitonin and IL-6 was 0.85 and 0.61, respectively. The combined performance of procalcitonin and IL-6 was similar to that of procalcitonin alone, AUC of 0.85. On univariate analysis, only procalcitonin and IL-6 were associated with blood culture positivity. Multivariate logistic regression analysis showed that only procalcitonin was associated with blood culture positivity (odds ratio, 12.15 [1.29-114.0] for levels above the median compared with levels below the median). Using procalcitonin cut points of 1.35 and 2.14 (nanogram per milliliter) enabled 100% and 90% identification of positive blood cultures and reduced the need of blood cultures by 47.5% and 57.5%, respectively.
  
  
  CONCLUSIONS
  Compared with IL-6, procalcitonin better predicts blood culture positivity in patients with sepsis. Using a predefined procalcitonin cut points will predict most positive blood cultures and reduce the need of blood cultures in almost half of patients with sepsis.
authors: Department of Internal Medicine B, Rambam Health Care Campus, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors: Mohammad
authors: M
authors: Naffaa
authors: Department of Internal Medicine B, Rambam Health Care Campus, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors: Badira F
authors: BF
authors: Makhoul
authors: Department of Internal Medicine B, Rambam Health Care Campus, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors: Amjad
authors: A
authors: Tobia
authors: Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel; The Laboratory of Clinical Biochemistry, Rambam Health Care Campus, Haifa, Israel.
authors: Marielle
authors: M
authors: Kaplan
authors: Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel; Heart Institute, Rambam Health Care Campus, Haifa, Israel; The Rappaport Family Institute for Research in the Medical Sciences, Technion, Israel Institute of Technology, Haifa, Israel.
authors: Doron
authors: D
authors: Aronson
authors: Department of Internal Medicine B, Rambam Health Care Campus, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel; The Rappaport Family Institute for Research in the Medical Sciences, Technion, Israel Institute of Technology, Haifa, Israel.
authors: Zaher S
authors: ZS
authors: Azzam
authors: Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel; Internal Medicine C, Ha'emek Medical Center, Afula, Israel. Electronic address: saliba_wa@clalit.org.il.
authors: Walid
authors: W
authors: Saliba
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007557:Israel; D008297:Male; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000097:blood*; D012307:Risk Factors; D018805:Sepsis / Q000097:blood*
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D015850:Interleukin-6; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide