Fecal Occult Blood Testing Should NOT Be Done
Fecal occult blood testing is of no benefit in the investigation of iron deficiency anemia and should not be performed. 1 Instead, this 79-year-old patient requires direct visualization of the gastrointestinal tract with upper and lower endoscopy.
Why FOBT is Not Indicated
- FOBT is insensitive and non-specific for detecting the sources of chronic blood loss that cause iron deficiency anemia 1
- The test performs poorly for proximal gut bleeding, which is a common source of iron deficiency 2
- Guidelines explicitly state that faecal occult blood testing is of no benefit in the investigation of IDA 1
- The presence or absence of positive FOBT results does not change management or predict which patients have significant gastrointestinal lesions 3, 4
What Should Be Done Instead
Upper and lower GI investigations should be considered in all postmenopausal female and all male patients where IDA has been confirmed unless there is a history of significant overt non-GI blood loss 1
Recommended Investigation Algorithm:
Gastroscopy (EGD) and colonoscopy should be the first-line investigations 1
Screen for coeliac disease - found in 3-5% of IDA cases 1
- Can be done serologically or via small bowel biopsy during gastroscopy 1
Urinalysis to exclude urinary tract bleeding 1
Important Clinical Considerations:
- Age 79 places this patient at higher risk for serious pathology including gastrointestinal malignancy 1
- The lower the hemoglobin, the more urgent the need for investigation 1
- Even if an upper GI lesion is found, colonoscopy should still be performed unless advanced gastric cancer is discovered 1
- Site-specific symptoms are unreliable - investigation should proceed regardless of symptom location 3, 4
Common Pitfall to Avoid:
Do not delay endoscopic investigation based on FOBT results or assume that NSAID use, anticoagulation, or minor upper GI findings (like gastritis or small ulcers) explain the anemia without completing full evaluation 1, 3, 5