Iron deficiency anaemia is the most common clinical presentation in adults.
Folate (and rarely vitamin B12) deficiency may lead to a macrocytic anaemia.
low Hb and microcytic hypochromic red cells
Order an IgA-tTG test in any patient with suspected coeliac disease.
Higher titres have increased positive predictive value. Serological testing should be done on a gluten-containing diet.
titre above normal range for laboratory
EMA is a more expensive alternative to IgA-tTG with greater specificity but lower sensitivity.
Perform initially if IgA-tTG is unavailable.
Order this test initially in any patient with skin lesions suggestive of dermatitis herpetiformis.
Both sensitivity and specificity are high.
granular deposits of IgA at the dermal papillae of lesional and perilesional skin by direct immunofluorescence
Test of choice for individuals with IgA deficiency.
IgG-tTG was previously one of the common serological tests for coeliac disease in individuals with known or suspected IgA deficiency. However, this test has been largely replaced by the newer and more accurate IgG DGP or IgA/IgG DGP (deamidated gliadin peptide).
The endoscopic appearance is not sensitive for diagnosis, and may be normal in up to one third of cases at diagnosis.
atrophy and scalloping of mucosal folds; nodularity and mosaic pattern of mucosa
Small-bowel histology is essential and the gold-standard test to confirm the diagnosis.
Biopsies should be performed while on a gluten-containing diet. Patients with an elevated IgA-tTG level should be referred for duodenal biopsy. Small intestinal biopsies should be obtained regardless of the IgA-tTG result in patients with a high clinical index of suspicion.
Two biopsies of the duodenal bulb and at least four biopsies of the distal duodenum should be submitted for histological analysis.
A single biopsy specimen should be collected with each pass of the forceps, to improve the diagnostic quality of the specimens.
Biopsy results are graded using the Marsh criteria.
presence of intra-epithelial lymphocytes, villous atrophy, and crypt hyperplasia
This genetic test is useful to rule out coeliac disease in patients already on a gluten-free diet or in patients with an idiopathic coeliac-like enteropathy.
positive HLA-DQ2 or HLA-DQ8
People with coeliac disease on a gluten-free diet prior to evaluation cannot be differentiated from healthy controls. In these patients, gluten challenge is necessary. In a gluten challenge, the person is placed back on a gluten-containing diet (at least 2 slices of wheat bread daily), and serological tests and small bowel histology assessed after 2 to 8 weeks on the gluten-containing diet.
increase in coeliac serological tests and presence of intra-epithelial lymphocytes, villous atrophy, and crypt hyperplasia on small intestinal biopsy
Video capsule endoscopy enables imaging of the entire small intestine and has good sensitivity for the detection of macroscopical features of coeliac disease. In 3% of cases, villous atrophy is only found in the jejunum, reducing the yield of upper endoscopy and duodenal biopsies for diagnosis.
Video capsule endoscopy is not recommended when a stricture is suspected.
atrophy and scalloping of mucosal folds; nodularity and mosaic pattern of mucosa; sensitive for the detection of villous atrophy
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