wip These pages are work in progress. Please add comments if you want. If you have material to submit send them to me via admin@wmsurgeons.com

Search:     Advanced search
Browse by category:
Contact Us
Home : Top directory : / Short topics / Colorectal / How does Faecal occult blood testing work?

How does Faecal occult blood testing work?

Author:Lengyel J.
on 15 May, 2007

Last edited by: Lengyel J. on 07 Oct, 2007
Print
Email to friend
Add comment
Views: 903
Votes: 2
Comments: 0
  • Available Tests
    1. Guaiac-Based Test (Hemoccult) ( used in th UK)
      1. Reagent derived from wood resin of Guajacum trees
      2. Reaction based on presence of Hemoglobin in sample
        1. Hemoglobin contains pseudoperoxidase
        2. Pseudoperoxidase converts guaiac to blue
        3. Reaction requires addition of hydrogen peroxide
    2. Heme-Porphyrin Test (Hemoquant)
      1. Quantifies porphyrins from Hemoglobin
      2. Advantages
        1. Measures amount of stool blood present
        2. Food-based peroxidases do not give false positives
      3. Disadvantages
        1. Expensive and requires increased lab staff time
        2. High false positive rate
    3. Immunochemical Fecal Occult Blood: HemeSelect, FECA-EIA
      1. Identifies only intact human Hemoglobin
      2. Advantages
        1. Ingested red meat does not give false positive
        2. Food-based peroxidases do not give false positives
        3. Specific for lower gastrointestinal tract bleeding
      3. Disadvantages
        1. Requires increased lab staff time
        2. Detects only lower gastrointestinal tract bleeding

     

     

  • Efficacy in Colon Cancer Screening (Guaiac tests)
    1. USPSTF Strength of Recommendation: B
    2. Screening picks up 26% of Colorectal Cancer
    3. Lowers Colon Cancer mortality (versus no screening)
      1. Annual screening: 33% reduction
      2. Biennial (every 2 years): 15-21% reduction
    4. References
      1. Kronberg (1996) Lancet 348:1467-71
      2. Hardcastle (1996) Lancet 348:1472-7
      3. Mandel (2000) N Engl J Med 343:1603-7
      4. Mandel (1999) J Natl Cancer Inst 91:434-7

     

     

    		•
    Others in this Category
    document Anastamotic leak rates
    document CR07 Summary
    document Management of a patient age 12 with Familial Adenomatous Polyposis (FAP)
    document Early adenocarcinomas of the colon and rectum (incl polyps)
    document Do you know about colorectal screening program?
    document What is the evidence for pelvic drainage following anterior resection?
    document When is surgery recommended after an episode of acute diverticulitis?
    document How do you classify Diverticular complications?
    document What is your preferred method of treating sigmoid volvulus?
    document How would you stage rectal cancers?
    document When do you operate after an episode of acute diverticulitis?
    document How would you treat someone with carcinoid of the appendix?
    document How would you go about investigating someone with chronic diarrhoea?
    document What do you do if you find a segment of terminal ileal crohns disease when you open for ? appendicitis?
    document What are the issues regarding Ileal pouch-anal anastomosis
    document Ileoanal pouches
    document What are the components of CR-POSSUM?
    document You find multiple hamartomas on OGD. What follow up should this patient with Peutz-Jeghers syndrome have?
    document What are the Amsterdam critieria? And what do they relate to?
    document How would you define severe UC. and when would you recommend a colectomy?
    document What is the wexner score?
    document How would you manage someone with peri anal crohns disease
    document Abdominal compartment sydrome (ACS)
    document Entero Cutaneous fistula
    document What is CEA?
    document How would you counsel a Jehovahs Witness for a Right Hemicolectomy
    document What is solitary rectal ulcer syndrome?
    document What are the components of CR-POSSUM?
    document Where would you find cacinoid andf how would you classify it?
    document What is "Enhanced ercovery" in the context of colorectal surgery?


    RSS
    Powered by KBPublisher (Knowledge base software)