🩸 Occult GI Bleeding Anemia Workup Simulator

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.