Clinical Utility of Routine Screening for IGA Deficiency in Samples Tested for EMA

Aims: The prevalence of coeliac disease in Ireland is approximately 1%. Serological screening is by either antiendomysial (immunofluoresence) or tissue transglutaminase (ELISA) antibody testing, both are IgA based and have a sensitivity and specificity of 97–98%. This creates a problem in IgA deficiency, the prevalence of which is approximately 2.5% in coeliac disease, which is 15–16 times greater than in the general population.

To avoid missing a diagnosis of coeliac disease in these cases, the current practice in the immunology department is to routinely screen all samples sent for anti-EMA testing for IgA deficiency.

This audit aimed to determine the impact of this practice on detection rates of coeliac disease.

Methods: Using computerised records we retrospectively reviewed 200 consecutive samples sent for anti-EMA screening. Medical case notes were used to confirm or exclude a diagnosis of coeliac disease.

Results: 3 of 200 samples tested were IgA deficient (1.5%).

10 of 200 samples tested were EMA positive (5%).

The patients with IgA deficiency were EMA negative but did not have coeliac disease on reviewing the case notes.

Conclusions: This data suggests that routine screening for IgA deficiency in samples tested for EMA has a low yield of detecting coeliac disease.