title: Defining the optimal cut-off values for liver enzymes in diagnosing blunt liver injury.
abstract: BACKGROUND
  Patients with blunt trauma to the liver have elevated levels of liver enzymes within a short time post injury, potentially useful in screening patients for computed tomography (CT). This study was performed to define the optimal cut-off values for serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in patients with blunt liver injury diagnosed with contrast enhanced multi detector-row CT (CE-MDCT).
  
  
  METHODS
  All patients admitted from May 2006 to July 2013 to Teikyo University Hospital Trauma and Critical Care Center, and who underwent abdominal CE-MDCT within 3 h after blunt trauma, were retrospectively enrolled. Using receiver operating characteristic (ROC) curve analysis, the optimal cut-off values for AST and ALT were defined, and sensitivity and specificity were calculated.
  
  
  RESULTS
  Of a total of 676 blunt trauma patients 64 patients were diagnosed with liver injury (Group LI+) and 612 patients without liver injury (Group LI-). Group LI+ and LI- were comparable for age, Revised Trauma Score, and Probability of survival. The groups differed in Injury Severity Score [median 21 (interquartile range 9-33) vs. 17 (9-26) (p < 0.01)]. Group LI+ had higher AST than LI- [276 (48-503) vs. 44 (16-73); p < 0.001] and higher ALT [240 (92-388) vs. 32 (16-49); p < 0.001]. Using ROC curve analysis, the optimal cut-off values for AST and ALT were set at 109 U/l and 97 U/l, respectively. Based on these values, AST ≥ 109 U/l had a sensitivity of 81%, a specificity of 82%, a positive predictive value of 32%, and a negative predictive value of 98%. The corresponding values for ALT ≥ 97 U/l were 78, 88, 41 and 98%, respectively, and for the combination of AST ≥ 109 U/l and/or ALT ≥ 97 U/l were 84, 81, 32, 98%, respectively.
  
  
  CONCLUSIONS
  We have identified AST ≥ 109 U/l and ALT ≥ 97 U/l as optimal cut-off values in predicting the presence of liver injury, potentially useful as a screening tool for CT scan in patients otherwise eligible for observation only or as a transfer criterion to a facility with CT scan capability.
authors.affiliation: Department of Emergency Medicine, Teikyo University Hospital, 2-11-1 Kaga, Itabashi, Tokyo, Japan. t-koyama@office.nifty.jp.|Department of Traumatology, Oslo University Hospital-Ulleval, Oslo, Norway. t-koyama@office.nifty.jp.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Koyama
authors.affiliation: Department of Emergency Medicine, Toranomon Hospital, Tokyo, Japan. hhamada@toranomon.gr.jp.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Hamada
authors.affiliation: Department of Emergency Medicine, Toranomon Hospital, Tokyo, Japan. qq-mn@toranomon.gr.jp.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Nishida
authors.affiliation: Department of Traumatology, Oslo University Hospital-Ulleval, Oslo, Norway. palnaess@online.no.
authors.forename: Paal A
authors.initials: PA
authors.lastname: Naess
authors.affiliation: Department of Traumatology, Oslo University Hospital-Ulleval, Oslo, Norway. tinagaar@online.no.
authors.forename: Christine
authors.initials: C
authors.lastname: Gaarder
authors.affiliation: Department of Emergency Medicine, Teikyo University Hospital, 2-11-1 Kaga, Itabashi, Tokyo, Japan. sakamoto.tetsuya@nifty.ne.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sakamoto
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood*; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000201:enzymology / Q000293:injuries; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D015599:Trauma Severity Indices; D014949:Wounds, Nonpenetrating / Q000097:blood* / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase
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