title: Faecal haemoglobin concentration is related to severity of colorectal neoplasia.
abstract: OBJECTIVE
  Guaiac faecal occult blood tests are being replaced by faecal immunochemical tests (FIT). We investigated whether faecal haemoglobin concentration (f-Hb) was related to stage in progression of colorectal neoplasia, studying cancer and adenoma characteristics in an evaluation of quantitative FIT as a first-line screening test.
  
  
  METHODS
  We invited 66 225 individuals aged 50-74 years to provide one sample of faeces. f-Hb was measured on samples from 38 720 responders. Colonoscopy findings and pathology data were collected on the 943 with f-Hb ≥ 400 ng Hb/ml (80 µg Hb/g faeces).
  
  
  RESULTS
  Of the 814 participants with outcome data (median age: 63 years, range 50-75, 56.4% male), 39 had cancer, 190 high-risk adenoma (HRA, defined as ≥ 3 or any ≥ 10 mm) and 119 low-risk adenoma (LRA). 74.4% of those with cancer had f-Hb>1000 ng Hb/ml compared with 58.4% with HRA, and 44.1% with no pathology. Median f-Hb concentration was higher in those with cancer than those with no (p<0.002) or non-neoplastic (p<0.002) pathology, and those with LRA (p=0.0001). Polyp cancers had lower concentrations than more advanced stage cancers (p<0.04). Higher f-Hb was also found in those with HRA than with LRA (p<0.006), large (>10 mm) compared with small adenoma (p<0.0001), and also an adenoma displaying high-grade dysplasia compared with low-grade dysplasia (p<0.009).
  
  
  CONCLUSIONS
  f-Hb is related to severity of colorectal neoplastic disease. This has ramifications for the selection of the appropriate cut-off concentration adopted for bowel screening programmes.
authors: Scottish Bowel Screening Centre, Kings Cross Hospital, Dundee, UK. jaynedigby@nhs.net
authors: Jayne
authors: J
authors: Digby
authors: Callum G
authors: CG
authors: Fraser
authors: Francis A
authors: FA
authors: Carey
authors: Paula J
authors: PJ
authors: McDonald
authors: Judith A
authors: JA
authors: Strachan
authors: Robert H
authors: RH
authors: Diament
authors: Margaret
authors: M
authors: Balsitis
authors: Robert J C
authors: RJ
authors: Steele
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005243:Feces / Q000737:chemistry*; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D006454:Hemoglobins