Clinical Use:
Background: Several diseases of the gastro-intestinal tract (e.g carcinoma of the bowel, duodenal ulcer, ulcerative colitis) result in greater than normal blood loss. Chronic and/or severe blood loss of this type may result in anaemia. The blood is often partly digested and homogenised into the faecal matter making it difficult to detect visually. Even blood that may be on the surface of formed stools, from bleeding low in the tract (e.g haemorrhoids), is often difficult to see on dark faeces. This necessitates the need for a test to detect hidden or ‘occult’ blood.

More recently, faecal occult blood measurement has been proposed as a screening test for colorectal carcinoma. 10% of people over 45 years of age have colorectal polyps. 1% of these will become malignant. Early detection of the lesions is known to increase patient survival rate considerably. Occult blood as a screening test relies on the fact that polyps larger than 0.5cm may bleed. A positive occult blood test is not diagnostic but suggests that the patient requires further investigations.

Reference Ranges: N/A
Associated Diseases:
Patient Preparation:
Specimen Requirements: Sample type:

  • Three consecutive stool samples should be collected for this procedure. Stools should be collected into plain, white top universal containers with no preservatives and should be free from any other material e.g tissue paper. All specimens should be clearly labelled and have an appropriate request form.
  • Specimens may also be received in the specific collecting device designed for this procedure. Collecting devices that are leaking/not fully closed or that are overfilled should be rejected. Please note only GP practices are supplied with the collecting devices NOT hospital wards, this is due to an infection control risk.

Sample identification:

  • Three patient identifiers from
    • Name
    • D.O.B.
    • Address
    • N.H.S. number
    • Unit Number

    should match on the specimen and request form.

Turnaround Time: 1 week
Additional Information:
Referred Test: