[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical skills](https://durgical.com/en/clinical-skills/) › [Other investigations](https://durgical.com/en/clinical-skills/areas/investigations/) › Capsule endoscopy

# Capsule endoscopy

- Investigation

The patient swallows a pill-sized camera that takes pictures of the small bowel as it passes through, and leaves the body naturally.

Updated Nov 13, 2026

## Key points

- Main indication: suspected small-bowel bleeding after a normal upper endoscopy and colonoscopy.
- It sees but cannot biopsy or treat: positive findings go to device-assisted enteroscopy or surgery.
- Key complication: capsule retention behind a stricture (Crohn disease, NSAID injury, radiation, tumour).
- Known or suspected stricture or obstruction: patency capsule or cross-sectional imaging first.
- No MRI until the capsule has been passed (it contains metal and electronics).

## What it is

Capsule endoscopy uses a disposable, pill-sized wireless camera that the patient swallows. As peristalsis carries it through the gut, it takes thousands of images and sends them to a recorder worn on the body, usually for most of a day; a trained reader then reviews the recording. Its main use is the small bowel, which standard upper endoscopy and colonoscopy cannot reach: suspected small-bowel bleeding (overt or occult bleeding, or iron-deficiency anaemia, after a normal upper endoscopy and colonoscopy), suspected or known small-bowel Crohn disease, complications of coeliac disease, polyposis syndromes and small-bowel tumours. It is painless and needs no sedation, but it cannot take biopsies, treat a lesion or be steered, and its position is only approximate. A positive finding is therefore followed by device-assisted enteroscopy (balloon or spiral) or surgery to sample or treat it. The key risk is capsule retention, in which the capsule stays behind a stricture; in patients with known or suspected strictures a dissolvable patency capsule or imaging is used first. MRI is avoided until the capsule has left the body.

## Indications

- Suspected small-bowel bleeding: overt bleeding or iron-deficiency anaemia with a normal upper endoscopy and colonoscopy.
- Suspected small-bowel Crohn disease, or assessing its extent and response when other tests are inconclusive.
- Coeliac disease that does not respond to diet, or suspected complications.
- Surveillance in polyposis syndromes and suspected small-bowel tumours.
- Colon capsule: selected patients who cannot have or did not complete colonoscopy.

## Contraindications

- Known or suspected bowel obstruction, stricture or fistula, unless patency has been shown first.
- Swallowing disorders or a risk of aspiration: the capsule can be placed endoscopically instead.
- Pregnancy: generally deferred until after delivery.
- A planned MRI before the capsule has passed.
- Implanted cardiac devices: no longer a bar in most units, but follow local policy.

## Preparation and what happens

- Explain the test, the recorder and the risk of retention, and get consent — retention may need endoscopy or surgery.
- Ask about obstructive symptoms, Crohn disease, NSAID use, abdominal radiation and surgery — these raise the risk of retention.
- Arrange a patency capsule or imaging if a stricture is possible — it shows whether a capsule can pass safely.
- Clear fluids the day before, then fasting overnight; bowel preparation if the unit uses it — a clean small bowel shows more mucosa.
- Stop iron tablets for some days before, as the unit advises — iron darkens the contents and hides the mucosa.
- On the day: sensors or a belt and the recorder are fitted, and the capsule is swallowed with water — the recorder stores the images.
- Clear fluids after a couple of hours and a light meal later, as instructed — early food slows transit and blurs the view.
- Keep the recorder on, avoid strong magnetic fields, and return it at the set time — the images are read afterwards.
- Watch for passage of the capsule; report pain, vomiting or distension — these may mean the capsule is stuck.

## Risks and complications

- Capsule retention: the capsule stays in the gut for at least two weeks or needs removal; more common with strictures.
- Incomplete study: the battery ends before the capsule reaches the colon (slow gastric or small-bowel transit).
- Aspiration of the capsule into the airway: rare, mainly in older patients or those with swallowing problems.
- Missed lesions: views are lost in fast segments or with poor preparation, and the duodenum and proximal jejunum are seen briefly.
- False positives: minor erosions and red spots are common and may not explain the bleeding.

## Next step

- Read the report: lesions found, approximate location (time from the pylorus) and whether the study reached the colon.
- A bleeding source or lesion: refer for device-assisted enteroscopy, from the mouth or the anus according to its position.
- Normal study with ongoing bleeding: repeat endoscopy, capsule or CT enterography; persistent anaemia needs a specialist review.
- Capsule not seen to pass and symptoms appear: abdominal radiograph to locate it; call a senior if there are signs of obstruction.
- Continue iron replacement and recheck the haemoglobin; the cause still needs a diagnosis.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main indication for capsule endoscopy?

Suspected small-bowel bleeding, overt or as iron-deficiency anaemia, after a normal upper endoscopy and colonoscopy.

## What is the most important complication of capsule endoscopy, and how is it prevented?

Capsule retention behind a stricture; in patients at risk, a patency capsule or imaging confirms the bowel is open before the real capsule.

## Why does a positive capsule endoscopy usually lead to another procedure?

The capsule cannot be steered, take biopsies or treat lesions, so device-assisted enteroscopy or surgery is needed to sample or treat the finding.

## Which imaging test must be avoided until the capsule has been passed?

MRI, because the capsule contains metal and electronics; if passage is uncertain, an abdominal radiograph checks first.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-skills/capsule-endoscopy/)

## Elsewhere in DurgiPedia

- [Upper and lower gastrointestinal bleeding](https://durgical.com/en/clinical-exam/upper-and-lower-gastrointestinal-bleeding/)
- [Absorption of iron, calcium and vitamin B12](https://durgical.com/en/physiology/absorption-of-iron-calcium-and-vitamin-b12/)
- [Small bowel and colon motility](https://durgical.com/en/physiology/small-bowel-and-colon-motility/)

## Connections

## Related 3

- [Upper GI endoscopy](https://durgical.com/en/clinical-skills/upper-gi-endoscopy/)
- [Colonoscopy and sigmoidoscopy](https://durgical.com/en/clinical-skills/colonoscopy-and-sigmoidoscopy/)
- [Reading a full blood count](https://durgical.com/en/clinical-skills/reading-a-full-blood-count/)

## Related conditions 5

- [Iron deficiency anaemia](https://durgical.com/en/conditions/iron-deficiency-anaemia/)
- [Crohn disease](https://durgical.com/en/conditions/crohn-disease/)
- [Coeliac disease](https://durgical.com/en/conditions/coeliac-disease/)
- [Small bowel obstruction](https://durgical.com/en/conditions/small-bowel-obstruction/)
- [Lower gastrointestinal bleeding](https://durgical.com/en/conditions/lower-gastrointestinal-bleeding/)

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Educational content; it does not replace supervised hands-on training, your institution's protocols or a prescriber's order. A procedure is learnt with a teacher and done only once you are trained to do it.

Sources: [Capsule Endoscopy](https://www.ncbi.nlm.nih.gov/books/NBK482306/) (StatPearls (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/clinical-skills/capsule-endoscopy/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-skills/capsule-endoscopy/