endoscopy biopsy
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Looking directly at the gut and taking tissue samples — the gold standard for confirming celiac diagnosis and grading damage.
Upper endoscopy (gastroscopy) combined with duodenal biopsy is the confirmatory step in celiac diagnosis. While blood tests provide strong indirect evidence, biopsy provides direct histological evidence of intestinal damage graded by the marsh-classification.
The Procedure
A flexible camera (endoscope) is passed through the mouth, down the oesophagus and stomach, into the duodenum (first section of the small intestine). Multiple tissue samples (biopsies) are taken from:
- Beyond the duodenal bulb (the very first segment, just after the stomach)
- The second and third parts of the duodenum
- Sometimes the jejunum
Why multiple samples? Celiac damage is patchy — a single biopsy from a healthy area would produce a false negative. Guidelines recommend 4–6 samples minimum.
What the Endoscopist Sees
Macroscopic (visible) features of active celiac on endoscopy:
- Scalloping of duodenal folds (irregular, scalloped edges instead of smooth circular folds)
- Fissures and cracks in the mucosa
- Mosaic pattern — cobblestone-like appearance
- Prominent submucosal blood vessels — visible through a thinner, atrophied mucosa
- Nodular mucosa
These features are suggestive but not diagnostic — biopsy is always needed for confirmation.
What the Pathologist Sees
Biopsy samples are sent to pathology for microscopic examination. The pathologist assesses:
- IEL count per 100 enterocytes
- Crypt hyperplasia (elongated crypts)
- Villous atrophy (degree of villi flattening)
These three features are graded on the marsh-classification scale.
Capsule Endoscopy
An alternative for patients unable or unwilling to undergo standard upper endoscopy. The patient swallows a pill-sized camera that photographs the intestinal lining as it travels through. Useful for visualising mucosal changes across a wider length of bowel, but cannot take biopsies — diagnostic, not confirmatory.
When Biopsy Can Be Skipped
Per ESPGHAN 2020 paediatric guidelines, biopsy can be avoided in children if:
- TTG IgA ≥10× the upper limit of normal
- EMA antibody positive
- Symptoms of celiac present
No equivalent no-biopsy pathway exists for adults yet.
Repeat Biopsy
Routine repeat biopsy is not recommended during follow-up unless symptoms persist. However, repeat biopsy may be warranted to confirm mucosal healing if there's no symptomatic improvement on GFD, or to investigate NRCD.
Related Concepts
marsh-classification | intraepithelial-lymphocytes | villous-atrophy | ttg-iga-test | gluten-challenge | small-intestine