To be diagnosed with coeliac disease, GPs will conduct a serological test (blood test) to detect antibodies (proteins in the blood that react against the body’s own cells/tissues) that may be generated in the bloodstream (for a person with the condition) when gluten is eaten. If a person has a positive antibody reading they will require a referral to a gastroenterologist (specialist) for an endoscopy and biopsy.
The initial serological tests will screen for anti-tissue transglutaminase antibodies (tTGA) or anti-endomysium antibodies (EMA). Serological testing for coeliac disease should not be offered to infants before gluten has been introduced into the diet (4).
Patients with IgA deficiency are at greater risk of presenting a false negative result if IgA-based serological tests are used diagnostically, which could result in under-diagnosis. In light of this, biopsies are required for a firm diagnosis (4). However, there are several limitations to biopsies e.g. potential poor orientation, fragmentation or inadequate sampling that could result in an incorrect diagnosis (5).
Through more sensitive serological tests, asymptomatic forms of the disease can also be detected. Research mainly from cohort studies in people with suspected coeliac disease has informed current NICE guidelines (4), providing recommendations (outlined below) to clinicians to recognise clinical symptoms and highlight when to offer serological tests in order to aid accurate diagnoses.