The knowledge about coeliac disease has increased a lot during last years. This has been possible due to the availability of new and more specific in vitro diagnostic medical devices.

Anti-gliadin antibody (AGA) detection is a still widely prescribed test, but its relevance has been decreasing since the introduction of endomysial antibody assay (EMA) and, a few years later, of anti-tTG antibodies (tTG), which sensitivity and specificity were better.

Yet, detection of AGA plays an important role in few specific situations such as children younger than 3 years and monitoring of gluten free diet.

Recent studies have shown that the use of synthetic peptides derived from gliadin as solid phase provides improved performances of these assays allowing to achieve better sensitivity and specificty values.

α-GliaPep IgA and α-GliaPep IgG are enzyme immunoassays for the quantitative detection of class IgA and IgG antibodies against gliadin specific peptides and have been developed to complete the Eurospital offer in the vitro diagnosis of coeliac disease.

• α-Glia-Pep IgA - code 9137 96 test
• α-Glia-Pep IgG - code 9138 96 test

Features of the product

• Antigen made up of specific gliadin derived peptide.
• High specificity
• Unique sample dilution for both lgA and lgG (1:100)
• The same sample dilution can be used with Eu-tTG lgA/lgG and α-Gliatest S chromo lgA/lgG kits
• Total incubation time.

Performance

A study has been carried out in three reference centres to evaluate diagnostic sensitivity and specificity of α-GliaPep lgA and lgG. The study included sera from clinically diagnosed coeliac patients, healthy patients and patients with food intolerance. Diagnosis of coeliac disease has benn based on intestinal biopsy following clinical symptoms and positive serology testing.

Results

α-GliaPep lgA & lgG
	Coeliac Subjects	Subjects with Food Intolerance	Healty subjects
Positive	98	3	4
Negative	22	23	128
Total	120	26	132

α-GliaPep lgA & lgG
Diagnostic Sensitivity	82 %
Diagnostic Specificity	97 % (95,6%)

Conclusion

The results achieved in the study show that α-GliaPep lgA and lgG have an improved sensitivity and a better specificity than classic anti-gliadin antibody test kits. Specificity is very high even when results from patients with food intolerance are considerer. As reported in the literature, patients with food intolerance might show falsely elevated positive results when tested for anti-gliadin antibody, namely lgG. These results may lead to wrong interpretation.

Whether to use α-GliaPep lgA and lgG or α-Gliatest S Chromo lgA and lgG depends upon the objectives of each clinical center.
if the objective is to identif coeliac patients, α-GliaPep and lg should be preferred due to their higher specificity which may almost completely exclude presence of false positive results.

On the other hand, if the objective is to monitor and/or look for possible alterations of the intestinal mucosa, α-gliatest S Chormo lgA and lgG might allow to detect possible shift of the antibody levels due to an alteration of the intestinal mucosa.