title: Screening for colorectal neoplasias with fecal occult blood tests: false-positive impact of non-dietary restriction.
abstract: OBJECTIVE
  Screening for colorectal cancer using guaiac-based fecal occult blood tests (gFOBT) is well established in Western populations, but is hampered by poor patient compliance due to the imposed dietary restrictions. Fecal immunochemical tests (FIT) do not require dietary restriction, but are more expensive than gFOBT and therefore restrict its use in developing countries in Asia. However, Asian diets being low in meat content may not require diet restriction for gFOBT to achieve equivalent results. The objective of this study was to evaluate and compare the validity and suitability of gFOBT and FIT or a combination of the two in screening for colorectal neoplasias without prior dietary restriction in an Asian population.
  
  
  METHODS
  Patients referred to the Endoscopic Unit for colonoscopy were recruited for the study. Stool samples were collected prior to bowel preparation, and tested for occult blood with both gFOBT and FIT. Dietary restriction was not imposed. To assess the validity of either tests or in combination to detect a neoplasm or cancer in the colon, their false positive rates, their sensitivity (true positive rate) and the specificity (true negative rate) were analyzed and compared.
  
  
  RESULTS
  One hundred and three patients were analysed. The sensitivity for picking up any neoplasia was 53% for FIT, 40% for gFOBT and 23.3% for the combination. The sensitivities for picking up only carcinoma were 77.8% , 66.7% and 55.5%, respectively. The specificity for excluding any neoplasia was 91.7% for FIT, 74% for gFOBT and 94.5% for a combination, whereas for excluding only carcinomas they were 84%, 73.4% and 93.6%. Of the 69 with normal colonoscopic findings, FOBT was positive in 4.3%, 23.2 %and 2.9% for FIT, gFOBT, or combination of tests respectively.
  
  
  CONCLUSIONS
  FIT is the recommended method if we are to dispense with dietary restriction in our patients because of its relatively low-false positivity and better sensitivity and specificity rates.
authors.affiliation: Cancer Research Institute, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: April Camilla
authors.initials: AC
authors.lastname: Roslani
authors.forename: Taufiq
authors.initials: T
authors.lastname: Abdullah
authors.forename: Kulenthran
authors.initials: K
authors.lastname: Arumugam
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D001208:Asia / Q000453:epidemiology; D031204:Caloric Restriction; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D005189:False Positive Reactions; D005243:Feces / Q000737:chemistry*; D005260:Female; D006138:Guaiac; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009780:Occult Blood; D010349:Patient Compliance; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D006138:Guaiac