Recently, areas of gliadin could be identified against which only patients with coeliac disease and not healthy individuals develop antibodies. These areas were fused by means of biomolecular methods (Institute of experimental Immunology, Luebeck, Germany) and as recombinant "gliadin-analogous fusion peptides" (GAF) form the basis of the innovative Anti-Gliadin(GAF-3X) ELISA.

In a multi-centre study this highly specific test was evaluated in cooperation with well-known national and international experts. A total of more than 900 sera were investigated: bioptically tested coeliac patients (n = 139), non-coeliac patients (bioptically tested; n = 145) and patients with rheumatic diseases (n = 626). In the investigation of this patient panel the new Anti-Gliadin(GAF-3X) ELISA showed a significantly higher sensitivity than the conventional Anti-Gliadin ELISA (calculated for a specificity of 95%).

For optimal diagnosis of coeliac disease antibodies against tissue transglutaminase (IgA) and against gliadin (GAF-3X) (IgG) should be investigated in parallel in suspected cases. This method offers three significant advantages:

• positive anti-tissue transglutaminase IgA results are confirmed with another highly specific test system
• the serological hit rate is increased because some patients do not exhibit antibodies against tTG
• the detection of IgG antibodies specific for coeliac disease is more reliable using the Anti-Gliadin (GAF-3X) ELISA than with the Anti-Tissue transglutaminase ELISA (Sensitivity: Anti-Gliadin (GAF-3X) ELISA (IgG): 85%, Anti-Tissue transglutaminase ELISA (IgG): 32%).

The investigation of antibodies with conventional anti-gliadin test systems is no longer considered to be state of the art.