Conditions the AGA-IgG Blood Test Can Diagnose

The AGA-IgG blood test is one of a panel of five celiac disease blood tests used to screen for and diagnose celiac disease. It's also been used to help identify non-celiac gluten sensitivity, although medical research shows it isn't particularly accurate for that purpose.

A doctor looking at a blood test
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AGA stands for antigliadin antibodies, which are specific antibodies produced by the body in response to contact with gliadin, a part of the gluten molecule. IgG stands for immunoglobulin G, which are general-purpose antibody molecules.

A positive AGA-IgG blood test indicates that the body may be mounting an immune system response to gluten ingestion, but it's considered less specific than other celiac blood tests. However, a positive AGA-IgG test can indicate celiac disease in a patient with IgA deficiency, which is a problem with your immune system that leaves you more susceptible to infections.

Uses

Since the AGA-IgG blood test can show your body is reacting to gluten (even if that reaction is not the specific one found in celiac disease), some physicians use the test as a tool to help them diagnose non-celiac gluten sensitivity.

However, medical research hasn't shown the test to work all that well. In a 2015 study, clinicians compared blood test results from people with suspected non-celiac gluten sensitivity with results from people with celiac disease and people with neither condition.

After evaluating the data, they concluded that the AGA-IgG blood test isn't a very sensitive test for non-celiac gluten sensitivity, which means it misses some people who actually do have the condition. The AGA-IgG test results can help with diagnosis, the researchers said, but only if the results are combined with other factors.

What Else Is the AGA-IgG Used For?

Elevated AGA-IgG levels have been found in some children diagnosed with autism. Studies have suggested autistic children who also have gastrointestinal symptoms can have higher levels of AGA-IgG than autistic children without digestive issues.

The AGA-IgG test also can be used to help diagnose gluten ataxia, a neurological autoimmune condition in which your body reacts to gluten ingestion by attacking a part of your brain. Gluten ataxia can cause a loss of coordination that affects your gait, your balance, and even your eyes. As such, physicians are generally advised to use the AGA-IgG blood test in concert with other blood tests if they suspect gluten ataxia.

5 Sources
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  3. Infantino M, Manfredi M, Meacci F, et al. Diagnostic accuracy of anti-gliadin antibodies in Non Celiac Gluten Sensitivity (NCGS) patients: A dual statistical approach. Clin Chim Acta. 2015;451(Pt B):135-41. doi:10.1016/j.cca.2015.09.017

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By Jane Anderson
Jane Anderson is a medical journalist and an expert in celiac disease, gluten sensitivity, and the gluten-free diet.