Unexplained Iron Deficiency Anemia — When to Suspect a Hidden Bleed
Placeholder: low iron with no clear cause triggers a GI bleeding workup.
- <30 ng/mL: Ferritin threshold (placeholder cutoff)
- ~30–60%: Occult bleed prevalence (placeholder estimate)
- >50 yr: Age flag for GI cancer (placeholder rule)
- GI workup: Referral pathway (placeholder next step)
Why unexplained IDA triggers GI evaluation
Placeholder: iron deficiency without diet/menstrual cause implies chronic blood loss.
Initial labs and history review
Placeholder: CBC, ferritin, and NSAID/anticoagulant history are checked first.
Placeholder: unexplained IDA in men or postmenopausal women warrants GI workup.
Fecal Occult Blood Testing — First-Line Stool Screen
Placeholder: guaiac or immunochemical stool tests detect microscopic blood.
- ~79%: FIT sensitivity (placeholder figure)
- ~94%: FIT specificity (placeholder figure)
- 1–3: Samples needed (placeholder protocol)
- ~1–2 days: Result turnaround (placeholder timing)
Guaiac vs immunochemical testing
Placeholder: FIT is more specific for human hemoglobin than guaiac cards.
Interpreting a positive result
Placeholder: a positive FOBT/FIT prompts endoscopic evaluation.
Placeholder: positive FOBT does not localize the bleed — imaging follows.
Upper Endoscopy (EGD) — Scoping the Upper GI Tract
Placeholder: EGD visualizes esophagus, stomach, and duodenum for lesions.
- Ulcers, gastritis: Common findings (placeholder list)
- ~15 min: Procedure time (placeholder duration)
- ~30–40%: Diagnostic yield (placeholder estimate)
- Yes: Biopsy capability (placeholder note)
Upper GI lesions causing occult bleeding
Placeholder: peptic ulcers, gastritis, and tumors are common causes.
When EGD is prioritized first
Placeholder: younger patients or NSAID users often get EGD first.
Placeholder: EGD first is common when upper GI symptoms dominate.
Colonoscopy — Scoping the Lower GI Tract
Placeholder: colonoscopy examines the colon for polyps, cancer, angiodysplasia.
- Polyps, CRC: Common findings (placeholder list)
- ~30 min: Procedure time (placeholder duration)
- ~30–50%: Diagnostic yield (placeholder estimate)
- >50 yr: Priority age (placeholder rule)
Lower GI lesions causing occult bleeding
Placeholder: colorectal cancer, polyps, and vascular lesions are key causes.
When colonoscopy is prioritized first
Placeholder: older patients or positive FOBT favor colonoscopy first.
Placeholder: colonoscopy is prioritized in patients over 50 with positive FOBT.
Bleeding Source Identification — Closing the Diagnostic Loop
Placeholder: the lesion is localized, biopsied, and anemia cause confirmed.
- ~70–90%: Combined yield (placeholder estimate)
- ~10–30%: No source found (placeholder — consider capsule endoscopy)
- Endoscopic, surgical: Treatment options (placeholder list)
- Repeat CBC/ferritin: Follow-up (placeholder plan)
Confirming and treating the source
Placeholder: biopsy confirms diagnosis; endoscopic therapy may stop bleeding.
When both scopes are negative
Placeholder: capsule endoscopy or CT enterography evaluates small bowel.
Placeholder: small bowel sources need capsule endoscopy if EGD/colonoscopy are negative.