title: Use of a faecal immunochemical test for haemoglobin can aid in the investigation of patients with lower abdominal symptoms.
abstract: BACKGROUND
  This study aimed to determine whether patients with lower abdominal symptoms can be investigated quickly using results of faecal haemoglobin concentration (f-Hb) measurements, and whether this test could form part of a diagnostic pathway for significant colorectal disease.
  
  
  METHODS
  Nine hundred and nine consecutive patients referred from primary care for colonoscopy were invited: 507 submitted samples for f-Hb measurement with a quantitative faecal immunochemical test for haemoglobin (FIT) (HM-JACKarc, Kyowa-Medex, Japan) and a diagnostic colonoscopy was completed in 484 patients.
  
  
  RESULTS
  Colorectal cancer (CRC), higher risk adenoma (HRA), inflammatory bowel disease (IBD) and/or colitis was found in 45 patients (9.3%); these had significantly higher (p<0.0001) f-Hb than the group of 243 with normal colonoscopy plus the 196 patients with less significant clinical findings. The 11 (2.2%) patients with CRC all had f-Hb >190 μg Hb/g faeces. Using a f-Hb cut-off of 10 μg Hb/g faeces, for the group with CRC or HRA or IBD or colitis, sensitivity was 68.9%, specificity 80.2%, positive predictive value (PPV) 26.3% and negative predictive value (NPV) 96.2%. Sensitivity and NPV were 100% for CRC suggesting f-Hb is a good rule-in test for CRC. Of the 243 patients with normal colonoscopy, 81.2% had f-Hb<10 μg Hb/g faeces.
  
  
  CONCLUSIONS
  The high NPV for significant colorectal diseases suggests that f-Hb could be used as a rule-out test in this context. Potential exists for using f-Hb measurements to investigate symptomatic patients and guide the use of colonoscopy resources: detailed algorithms for the introduction of f-Hb measurements requires further exploration.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Godber
authors.forename: Louise M
authors.initials: LM
authors.lastname: Todd
authors.forename: Callum G
authors.initials: CG
authors.lastname: Fraser
authors.forename: Linda R
authors.initials: LR
authors.lastname: MacDonald
authors.forename: Hakim Ben
authors.initials: HB
authors.lastname: Younes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003092:Colitis / Q000175:diagnosis* / Q000601:surgery; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000601:surgery; D005243:Feces / Q000737:chemistry*; D005260:Female; D006403:Hematologic Tests; D006454:Hemoglobins / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007120:Immunochemistry / Q000379:methods*; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D006454:Hemoglobins