title: Laboratory test variables useful for distinguishing upper from lower gastrointestinal bleeding.
abstract: OBJECTIVE
  To distinguish upper from lower gastrointestinal (GI) bleeding.
  
  
  METHODS
  Patient records between April 2011 and March 2014 were analyzed retrospectively (3296 upper endoscopy, and 1520 colonoscopy). Seventy-six patients had upper GI bleeding (Upper group) and 65 had lower GI bleeding (Lower group). Variables were compared between the groups using one-way analysis of variance. Logistic regression was performed to identify variables significantly associated with the diagnosis of upper vs lower GI bleeding. Receiver-operator characteristic (ROC) analysis was performed to determine the threshold value that could distinguish upper from lower GI bleeding.
  
  
  RESULTS
  Hemoglobin (P = 0.023), total protein (P = 0.0002), and lactate dehydrogenase (P = 0.009) were significantly lower in the Upper group than in the Lower group. Blood urea nitrogen (BUN) was higher in the Upper group than in the Lower group (P = 0.0065). Logistic regression analysis revealed that BUN was most strongly associated with the diagnosis of upper vs lower GI bleeding. ROC analysis revealed a threshold BUN value of 21.0 mg/dL, with a specificity of 93.0%.
  
  
  CONCLUSIONS
  The threshold BUN value for distinguishing upper from lower GI bleeding was 21.0 mg/dL.
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tomizawa
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Fuminobu
authors.initials: F
authors.lastname: Shinozaki
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Rumiko
authors.initials: R
authors.lastname: Hasegawa
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Shirai
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Motoyoshi
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Sugiyama
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Minoru Tomizawa, Department of Gastroenterology, National Hospital Organization Shimoshizu Hospital, Chiba 284-0003, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishige
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D001806:Blood Urea Nitrogen; D003113:Colonoscopy; D003937:Diagnosis, Differential; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D006454:Hemoglobins
keywords: Blood urine nitrogen; Hemoglobin; Likelihood analysis; Logistic regression analysis; Receiver-operator characteristic analysis