title: Diagnostic yield of a one sample immunochemical test at different cut-off values in an organised screening programme for colorectal cancer.
abstract: BACKGROUND
  Quantitative immunochemical faecal occult blood tests have become the recommended tests for colorectal cancer screening. The aim of this study was to complete our knowledge on the performance of one of the quantitative immunochemical tests available, FOB-Gold, and to propose a possible strategy for an organised screening programme.
  
  
  METHODS
  Within the French organised screening programme, 23,231 average-risk individuals, aged 50-74 performed both a 3-day Hemoccult test and a 1-day FOB-Gold test. Performances of the immunochemical test were evaluated at different cut-off levels.
  
  
  RESULTS
  The positivity rate for the Hemoccult was 2.1% and for the FOB-Gold varied between 4.6% (cut-off value of 100 ng/mL, the lowest studied cut-off) and 2.1% (cut-off value of 352 ng/mL). The number of colonoscopies decreased with increasing cut-off values by 21.5% (150 ng/mL), 35.4% (200 ng/mL) and 53.3% (352 ng/mL). The corresponding miss rate for CRC was respectively 6.4%, 11.1% and 22.2%, and for advanced adenoma respectively 16.3%, 29.2% and 43.6%. Compared with the reference cut-off for the FOB-Gold (100 ng/mL) the miss rate for Hemoccult was 53% for CRC and 77% for advanced adenoma.
  
  
  CONCLUSIONS
  The study suggests that in countries with colonoscopy facilities compatible with a screening test positivity rate of up to 5%, use of a 1-day test with a cut-off value between 100 and 150 ng/mL could be the recommended strategy. Further increasing the cut-off value up to the same positivity rate as Hemoccult could be used in areas with limited access to colonoscopy.
authors.affiliation: Registre Bourguignon des Cancers Digestifs, INSERM U866, Université de Bourgogne, 7 boulevard Jeanne d'Arc, Dijon Cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Hamza
authors.forename: V
authors.initials: V
authors.lastname: Dancourt
authors.forename: C
authors.initials: C
authors.lastname: Lejeune
authors.forename: J M
authors.initials: JM
authors.lastname: Bidan
authors.forename: C
authors.initials: C
authors.lastname: Lepage
authors.forename: J
authors.initials: J
authors.lastname: Faivre
mesh_terms: D000368:Aged; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods; D006403:Hematologic Tests / Q000379:methods*; D006801:Humans; D007120:Immunochemistry / Q000379:methods*; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009780:Occult Blood; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Colorectal cancer; Immunochemical faecal occult blood tests; Screening