title: Validity of immunological faecal occult blood screening for colorectal cancer: a follow up study.
abstract: OBJECTIVE
  Immunological faecal occult blood testing has been recognised as a useful method for wide scale screening of colorectal cancer in Japan during the past few years. This study was carried out to evaluate the validity of an immunological faecal occult blood test for colorectal cancer screening.
  
  
  METHODS
  A screening programme for colorectal cancer using an immunological faecal occult blood test was conducted on 3365 residents of regions within Nagano prefecture in 1991, and all the subjects were followed up for three years by verification from cancer registration. Based on the incidence of false negative cases among those who had been evaluated as normal by this screening, but were diagnosed as having colorectal cancer, the sensitivity and the specificity of this test were estimated.
  
  
  RESULTS
  Four false negative cases were found during the subsequent three year follow up period after screening. Among these four cases, one case was within the first follow up year, one case within the second year, and two cases within the third year. Accordingly, the sensitivity of this test was calculated as 90.9% within one year, 83.3% within two years, and 71.4% within three years, while the specificity was found to be 95.6%, indicating a validity higher than that achieved by a chemical occult blood test.
  
  
  CONCLUSIONS
  These findings suggest that the immunological faecal occult blood test has a high diagnostic accuracy and is a useful strategy for colorectal cancer screening.
authors.affiliation: Department of Public Health, Shinshu University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakama
authors.forename: N
authors.initials: N
authors.lastname: Kamijo
authors.forename: A S
authors.initials: AS
authors.lastname: Abdul Fattah
authors.forename: B
authors.initials: B
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000517:prevention & control*; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D007564:Japan; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000706:statistics & numerical data; D008875:Middle Aged; D009780:Occult Blood; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors