Gluten Sensitivity Diagnosis

How is Non-Celiac Gluten Sensitivity diagnosed?

Until recently, Non-Celiac Gluten Sensitivity has been diagnosed when gastroenterological or other symptoms disappear quickly once a person avoids gluten and reappear when that person later again eats gluten.

In 2015, researchers suggested criteria for a more formal diagnosis, to include:

  • patients' responses to a “modified version of the Gastrointestinal Symptom Rating Scale” 
  • “clinical response to the gluten-free diet”  “double-blind placebo-controlled gluten challenge” that contains “cooked, homogenously distributed gluten” and 
  • a standard for determining whether differences between gluten and placebo challenges can “discriminate a positive from a negative result.” 

More information on this criteria is at this Celiac Support Group blog post:  NCGS, CD & IBS research updates.

IgE tests (skin prick tests) are used to diagnose wheat allergy. They are not used to diagnose Non-Celiac Gluten Sensitivity.

Like Celiac Disease, Non-Celiac Gluten Sensitivity may result in increased intestinal permeability (sometimes called “leaky gut”), where antigens cross the intestinal mucosal barrier and result in the creation of anti-gliadin antibodies.

However, the IgA blood tests for small intestinal damage in Celiac Disease usually are negative in Non-Celiac Gluten Sensitivity. IgG tests for antibodies to deamidated gliadin (from tTG, which modifies gliadin) also usually are negative in Non-Celiac Gluten Sensitivity. IgG tests for antibodies to gliadin itself are present in more than half of those diagnosed with Non-Celiac Gluten Sensitivity, but the rate of these in Celiac Disease is even higher. Accordingly, blood tests for Non-Celiac Gluten Sensitivity may include tests for gluten peptides in addition to those included in the Celiac blood panel.

An endoscopy may show inflammation in the small intestinal mucosa. This would cause malabsorption of nutrients, just as in Celiac Disease. If there is inflammation, but no villous atrophy, this may indicate Non-Celiac Gluten Sensitivity.  If the endoscopy is negative, Non-Celiac Gluten Sensitivity remains a possibility.  

Non-Celiac Gluten Sensitivity is estimated to affect about 1% to 6% of the population. 

Very Important note from Celiac Support Group to anyone who thinks they might have a problem with gluten: Do not go gluten free before being tested for celiac disease! Otherwise, these diagnostic tests for celiac disease may be falsely negative, and to know for sure will require a patient to eat a bunch of gluten again before retesting (doctors’ timetables may differ).

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