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PTD - 234

Test Directory - Faecal Occult Blood (FOB)

Clinical Indications

The use of the Faecal occult blood test should be restricted to patients in whom endoscopy is contra-indicated e.g. they are low risk, age or co-morbidities. This includes:
Investigation of symptomatic patients when bowel visualisation is contra-indicated or difficult.
Follow-up of known disease (monitoring)
Investigation of familial colorectal cancer in patients <50 years who are low risk.

Asymptomatic patients over 60 yrs should be enrolled in the NHS Bowel Cancer Screening Programme ( which offers screening every two years to all men and women aged 60 to 69. People over 70 can request a screening kit by calling the freephone helpline 0800 707 6060. 

FOB is not indicated in patients with 'red flag' symptoms who should be referred urgently.
NICE 'red flag' symptoms for urgent referral
40 yrs with rectal bleeding & change in bowel habit for 6 weeks
60 yrs with rectal bleeding & without change in bowel habit for 6 weeks
60 yrs without rectal bleeding, but change in bowel habit for 6 weeks
Any age with palpable abdominal mass consistent with bowel involvement
Any age with palpable rectal mass
Non-menstruating women with unexplained iron deficiency anaemia and a Haemoglobin (Hb) ≤ 10 g/dL
Any age men with unexplained iron deficiency anaemia and Hb ≤ 11 g/dL

The evidence base for FOBs is based upon assaying a bowel movement from three consecutive days.

Request Form

Combined Pathology Blood form (Yellow/Black)


On request

Specific Criteria

Samples referred to Basildon Hospital for Faecal Occult Blood analysis from other Hospitals should be packaged in accordance with our transportation policy and will be assumed to have met the specific criteria of the referring laboratory.

Patient Preparation


None required.

Turnaround Time

Same day




1 mL


Blue top universal x3 (please send all 3 samples together).


No specific collection conditions.

Causes for Rejection

Unlabelled sample, not meeting specific criteria


A negative result does NOT rule out bowel pathology (even 3 negative
FOBs may miss 60% of colorectal cancers). Positive results require further investigations.

Lab. Handling

Processing: Label with a orange sticker, and store samples at 4C in separating fridge (CB39), FOB box.

Version 1.1 / October 2014                                                                                                    Approved by: Consultant Biochemist