Coeliac Disease - Diagnosis

Diagnosis

There are several tests that can be used to assist in diagnosis. The level of symptoms may determine the order of the tests, but all tests lose their usefulness if the patient is already taking a gluten-free diet. Intestinal damage begins to heal within weeks of gluten being removed from the diet, and antibody levels decline over months. For those who have already started on a gluten-free diet, it may be necessary to perform a re-challenge with some gluten-containing food in one meal a day over 2–6 weeks before repeating the investigations.

Combining findings into a prediction rule to guide use of endoscopic biopsy reported a sensitivity of 100% (it would identify all the cases) in a population of subjects with a high index of suspicion for coeliac disease, with a concomitant specificity of 61% (a false positive rate of 39%). The prediction rule recommends that patients with high-risk symptoms or positive serology should undergo endoscopic biopsy of the second part of the duodenum. The study defined high-risk symptoms as weight loss, anaemia (haemoglobin less than 120 g/l in females or less than 130 g/l in males), or diarrhoea (more than three loose stools per day).