title: Test characteristics of faecal immunochemical tests (FIT) compared with optical colonoscopy.
abstract: BACKGROUND
  Faecal occult blood tests are often the initial test in population-based screening. We aimed to: 1) compare the results of single sample faecal immunochemical tests (FITs) with colonoscopy, and 2) calculate the sensitivity for proximal vs. distal adenomatous polyps or cancer.
  
  
  METHODS
  Individuals scheduled for a colonoscopy were invited to complete a FIT prior to their colonoscopy preparation. FIT results were classified as positive, negative, or invalid. Colonoscopy reports were reviewed and abstracted. Because of product issues, four different FIT manufacturers were used. The test characteristics for each FIT manufacturer were calculated for advanced adenomatous polyps or cancer according to broad reason for colonoscopy (screening or surveillance/diagnostic).
  
  
  RESULTS
  Of those invited, 1,026 individuals (43.9%) completed their colonoscopy and had a valid FIT result. The overall sensitivity of the FITs (95% confidence intervals) was 0.18 (0.10 to 0.28) and specificity was 0.90 (0.87 to 0.91) for advanced adenomas or cancer. The sensitivity for distal lesions was 0.23 (0.11 to 0.38) and for proximal lesions was 0.09 (0.02 to 0.25). The odds ratio of an individual with a distal advanced adenoma or cancer testing positive was 2.68 (1.20 to 5.99). The two individuals with colorectal cancer tested negative, as did one individual with high-grade dysplasia.
  
  
  CONCLUSIONS
  The sensitivity of a single-sample FIT for advanced adenomas or cancer was low. Individuals with distal adenomas had a higher odds of testing positive than those with proximal lesions or no lesions.
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242 Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242 barcey-levy@uiowa.edu.
authors: Barcey T
authors: BT
authors: Levy
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242 Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242.
authors: Camden
authors: C
authors: Bay
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.
authors: Yinghui
authors: Y
authors: Xu
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.
authors: Jeanette M
authors: JM
authors: Daly
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.
authors: George
authors: G
authors: Bergus
authors: Department of Internal Medicine, Division of Gastroenterology, Carver College of Medicine, Iowa City, IA 52242.
authors: Jeffrey
authors: J
authors: Dunkelberg
authors: Department of Family Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242.
authors: Carol
authors: C
authors: Moss
mesh_terms: D018256:Adenomatous Polyps / Q000175:diagnosis*; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity
keywords: colonoscopy; colorectal cancer; colorectal cancer screening; fecal immunochemical test; sensitivity; specificity; test characteristics