Screening for coeliac disease in apparently healthy blood donors.

As gliadin is a common food antigen for many people, we have developed an ELISA for the detection of class-specific antigliadin antibodies (AGA), with which sera from a large population of apparently healthy blood donors was analysed. A very high prevalence (1/256) of positive AGA was found. However, the positive predictive value (+PV) was found to be very low, 20% for IgA-AGA and 0% for IgG-AGA alone. When screening large populations with no or few symptoms, it is desirable to have a high +PV to avoid unnecessary biopsies. IgA antiendomysium antibodies (IgA-EMA) were evaluated both as a single test and in combination with IgA-AGA. When screening individuals for CD in a population with no or few symptoms the easy and cheap IgA-AGA assay should be used as a first test and the IgA-EMA to verify the diagnosis and avoid unnecessary biopsies.