A literature review of 2014 found that non-coeliac<unk>  sensitivity diagnosis can be reached only by excluding celiac disease (CD) and wheat allergy. Persons suspected of having celiac disease may undergo serological testing for IgA anti-tissue transglutaminase antibodies (abbreviated anti-tTG antibodies or anti-TG2 antibodies) and anti-endomysial antibodies (abbreviated EMA) provided the IgA-level is high, and if IgA is low, testing for certain IgG antibodies; in case of positive serological indication, a duodenal biopsy may confirm active celiac disease. Eliminating the possibility of CD can generally also be done by adding HLA-DQ typing. The absence of HLA-DQ2 and HLA-DQ8 has a very high negative predictive value for CD, and the predictive value can be further enhanced by including HLA-DQ7.5 (HLA-DQ2 and HLA-DQ8 are found in coeliac disease 98% of the time in Caucasians, HLA-DQ7.5 present in the remaining 1.6% and only 0.4% of Caucasians are missed with the combination of these three). Without serological or HLA-DQ2/8 positivity, celiac disease is likely not present. HLA-DQ typing has a practical advantage in that it is the only diagnostic test that allows to exclude CD when a person is already on a<unk> -free diet; however, as not only celiacs are HLA-DQ2/HLA-DQ8 positive, this method has a higher false positive rate than anti-TG2 and EMA antibody testing. A four-of-five rule was proposed 2010 for confirming celiac disease, with the disease confirmed if at least four of the following five criteria are satisfied: *typical symptoms of celiac disease; *positivity of serum celiac disease immunoglobulin, A class autoantibodies at high titer; *human leukocyte antigen (HLA)-DQ2 or DQ8 genotypes; *celiac enteropathy at the small bowel biopsy; and *response to the<unk> -free diet. For diagnosis of wheat allergy, allergy tests are available.
Gluten-related disorders
Glycogen storage disease
Inborn errors of carbohydrate metabolism
Gerstmann–Sträussler–Scheinker syndrome
Sandhoff disease
Protein poisoning
Glycine encephalopathy
Gangliosidosis