GI Investigations · Patient Guide
Iron-Deficiency Anaemia: Which Investigations Do You Actually Need?
Low iron is a finding, not a diagnosis. In most adults, the question is where the iron is being lost — and the answer is usually sought in the gut.
Iron-deficiency anaemia means the body's iron stores have run down — commonly from chronic, invisible blood loss. In adults without an obvious explanation, the gut is the prime suspect, because it can bleed silently for months. That's why the standard work-up sounds aggressive but isn't: examining both ends, gastroscopy and colonoscopy, usually in a single visit.
Why both ends get examined
A bleeding point causing iron deficiency can sit anywhere from the oesophagus to the rectum — ulcers, inflammation, coeliac disease, polyps or tumours. Neither examination alone covers the territory, and dual pathology is common enough that finding one cause doesn't always excuse skipping the other end. Coeliac screening and duodenal biopsies are folded into the same work-up.
When this test is usually indicated
- Confirmed iron-deficiency anaemia in men of any age — this always warrants investigation
- Confirmed iron deficiency in post-menopausal women
- Pre-menopausal women when the deficiency is out of proportion to menstrual loss, or with any gut symptoms
- Iron deficiency with a positive FIT test or any bowel symptom
- Recurrent deficiency after previous correction without an established cause
When it may not be the right test
- Mild low-normal ferritin without true anaemia and with an obvious dietary or menstrual explanation — correction and confirmation may come first
- Repeating endoscopy for stable, explained deficiency already fully investigated
- Iron infusion or tablets as a substitute for finding the cause in unexplained cases
- Investigating acute blood-loss anaemia (surgery, childbirth) as if it were chronic occult loss
Where both examinations are normal and deficiency persists or recurs, attention turns to the small bowel — capsule endoscopy — and to non-gut causes. The sequencing matters: the common, treatable territory is examined properly first.
What happens if you do need it
The efficient version is both examinations in one visit under one sedation, with coeliac biopsies taken at the same time — precisely how Mr Papettas, JAG dual-accredited in colonoscopy and gastroscopy, runs the anaemia pathway. Iron replacement proceeds in parallel; finding the cause and fixing the count are complementary, not either/or.
Frequently asked questions
Why investigate if iron tablets fix my blood count?
Because tablets treat the consequence, not the cause. Unexplained deficiency can be the earliest sign of significant, treatable disease — including early bowel cancer.
Do gastroscopy and colonoscopy really happen on the same day?
Yes, routinely — one attendance, one sedation, both ends examined and biopsies taken as needed.
What causes iron deficiency besides bleeding?
Poor absorption (notably coeliac disease), diet, and increased demand. The work-up screens for absorption problems alongside blood loss.
What is ferritin?
The blood measure of iron stores — low ferritin confirms true iron deficiency rather than another type of anaemia.
What if both examinations are normal?
Deficiency that persists moves the search to the small bowel with capsule endoscopy, alongside a review of non-gut causes.
How quickly can the work-up happen privately?
Consultation, bloods, and dual endoscopy typically within days — call 01926 935121.
Related reading
Unsure whether you need this test?
Mr Trif Papettas FRCS is a Consultant Colorectal and General Surgeon at Nuffield Health Warwickshire Hospital, Leamington Spa, and a JAG dual-accredited endoscopist. A consultation settles which investigation, if any, your symptoms actually need — and if a test is indicated, it can usually be arranged within days.
Self-referrals welcome · No GP letter required · Self-pay and insured patients seen at Nuffield Health Warwickshire Hospital, Leamington Spa CV32 6RW