Investigations

Coeliac Disease – Investigations
Blood Tests
- serology by blood test; useful in diagnosing and excluding coeliac disease
- 4 types: modern – IgA antibodies against endomysium or tissue transglutaminase
older – IgA antibodies against reticulin or gliadin
- should still be followed by an endoscopy
- based on indirect immunofluorescence or ELISA
- total serum IgA level should be checked as some patients may have IgA deficiency

Endoscopy
- upper endoscopy with biopsy of the distal duodenum or proximal jejunum should be performed
- important to obtain multiple samples from the duodenum because not all areas equally affected (false negative)
- most have a small bowel that appears normal on endoscopy; main findings are scalloping of the small bowel folds, paucity in the folds, mosaic pattern to the mucosa, prominence of the submucosal blood vessels, and a nodular pattern to the mucosa
The classic pathology changes of coeliac disease in the small bowel are categorized by the "Marsh classification":
- Marsh stage 0: normal mucosa
- Marsh stage 1: increased number of intra-epithelial lymphocytes, usually exceeding 20 per 100 enterocytes
- Marsh stage 2: proliferation of the crypts of Lieberkuhn
- Marsh stage 3: partial or complete villous atrophy
- Marsh stage 4: hypoplasia of the small bowel architecture

Other tests
- full blood count
- electrolytes
- calcium
- renal function
- liver enzymes
- vitamin B12
- folic acid level
- coagulation tests (PT & aPTT) for vitamin K deficiency

(Posted by: Vivian)