title: The performance of three-sample qualitative immunochemical fecal test to detect colorectal adenoma and cancer in gastrointestinal outpatients: an observational study.
abstract: BACKGROUND
  Repeated qualitative fecal immunochemical test (qlFIT) is a clinical strategy widely used to detect lower gastrointestinal lesions, but its diagnostic power has not been assessed in opportunistic screening for colorectal neoplasia.
  
  
  OBJECTIVE
  This study aimed to determine the performance of three-sample qlFIT in screening for colorectal cancer and its precursors in high-risk participants.
  
  
  METHODS
  513 gastrointestinal outpatients yielded three qlFITs before a standard colonoscopy. We evaluated the diagnostic value of one, two, and three positive qlFITs serving as the positivity threshold. The risk factors of colorectal neoplasia to yield positive qlFITs were also determined.
  
  
  RESULTS
  52 patients were diagnosed with colorectal cancer and 70 with advanced adenomatous polyp. For colorectal cancer, the sensitivity and specificity of one positive qlFIT were 90.4% and 53.8%, of two were 80.8% and 75.1%, and of three were 53.9% and 88.5%, respectively. For advanced adenomatous polyp, the sensitivity and specificity of one positive qlFIT were 81.4% and 54.2%, of two were 50.0% and 72.5%, and of three were 28.6% and 86.2%. Left-sided location (OR 2.50, 95%CI 1.26-4.95) and advanced histology of tumors (OR 3.08, 95%CI 1.58-6.01) were independently associated with positive qlFITs.
  
  
  CONCLUSIONS
  Three-sample qlFIT is a reasonably good method to detect colorectal neoplasia in high-risk population. Tumors in the left side or with advanced pathological features are more likely to produce positive qlFITs.
authors.affiliation: Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Luo
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Wei-Xun
authors.initials: WX
authors.lastname: Zhou
authors.affiliation: Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Jia-Ming
authors.initials: JM
authors.lastname: Qian
authors.affiliation: Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
authors.forename: Jing-Nan
authors.initials: JN
authors.lastname: Li
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005243:Feces; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010045:Outpatients; D012189:Retrospective Studies; D055815:Young Adult