title: Sensitivity of immunochemical faecal occult blood testing for detecting left- vs right-sided colorectal neoplasia.
abstract: BACKGROUND
  Faecal occult blood tests (FOBTs) are used for colorectal cancer (CRC) screening. We aimed to assess the sensitivity of an immunochemical FOBT for detecting advanced colorectal neoplasia in the left vs the right colon and to explore reasons for potential differences in site-specific test performance.
  
  
  METHODS
  We prospectively measured faecal occult blood levels by a quantitative immunochemical FOBT (RIDASCREEN) in 2310 average-risk subjects undergoing screening colonoscopy. We compared diagnostic performance for subjects with left- vs right-sided advanced neoplasia, as well as patient characteristics and adenoma characteristics that have been suggested to impact faecal haemoglobin levels.
  
  
  RESULTS
  Sensitivities for subjects with left- vs right-sided advanced neoplasia were 33% (95% confidence interval (CI), 26-41%) and 20% (CI, 11-31%) (P=0.04) at a specificity of 95% (overall sensitivity: 29%) and the areas under the receiver-operating characteristics curve were 0.71 (CI, 0.69-0.72) and 0.60 (CI, 0.58-0.63), respectively. Pedunculated shape was strikingly more common in participants with left- vs right-sided advanced neoplasia (47% vs 14%). In logistic regression analyses adjusted for site, pedunculated shape was statistically significantly associated with test sensitivity (P=0.04).
  
  
  CONCLUSIONS
  The immunochemical FOBT in our study was more sensitive for detecting subjects with left- vs right-sided advanced colorectal neoplasia. Our findings may stimulate further diagnostic research in the field as well as modelling analyses to estimate the potential effect of site-specific test performance on the effectiveness of annual or biennial FOBT-based screening programmes, in particular with respect to protection from right-sided CRC.
authors.affiliation: Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 460, Heidelberg 69120, Germany. u.haug@dkfz.de
authors.forename: U
authors.initials: U
authors.lastname: Haug
authors.forename: K M
authors.initials: KM
authors.lastname: Kuntz
authors.forename: A B
authors.initials: AB
authors.lastname: Knudsen
authors.forename: S
authors.initials: S
authors.lastname: Hundt
authors.forename: H
authors.initials: H
authors.lastname: Brenner
mesh_terms: D000236:Adenoma / Q000175:diagnosis; D000368:Aged; D003113:Colonoscopy / Q000592:standards; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity