Gluten Sensitivity Diagnosis

Wondering if you are sensitive to gluten?

This blog is all about how to most accurately diagnose gluten sensitivity. This is part 2 of a 4-part series of blogs on this topic, so check out What is gluten sensitivity?, How to live gluten-free, and Why gluten sensitivity.

Celiac disease vs. gluten sensitivity:

• Celiac disease is a condition in which eating gluten causes damage to the small intestine which impacts the ability to absorb nutrients from food
• Gluten sensitivity is less specific – it includes medical conditions which are caused by and made worse by exposure to gluten and covers patients who feel better while gluten-free but may not fit the definition of celiac disease

Signs and symptoms:

Common:

• Diarrhea
• Fatigue
• Borborygmus (fun word for rumbling or gurgling in the abdomen)
• Abdominal pain
• Weight loss
• Abdominal distention/bloating
• Flatulence
• Irritability, mood swings (especially children)
• Short stature

Less common:

• Osteopenia/osteoporosis (especially premature)
• Abnormal liver function
• Nausea, vomiting
• Iron-deficiency anemia
• Neurological dysfunction
• Constipation

Diagnosis of gluten sensitivity and celiac

Diagnosis seems to be constantly changing and evolving, so I’ll share what my current knowledge is on the subject from my own experience being tested and what I use with my patients.

Diagnosis of Celiac Disease:

To unequivocally diagnose celiac disease, a patient must complete 3 steps:

1. Blood tests: must be eating gluten regularly (I recommend at least 1 serving daily for at least 3-4 weeks) before testing

• Serum immunoglobulin A (IgA) must be normal (rule-out IgA deficiency)
• Endomysial antibodies (IgA)
• Tissue transglutaminase (tTG) IgA antibodies

2. Small intestine biopsy to identify atrophy of the villi (numerous small projections that make up the absorptive surface of your small intestines

3. Positive results from a gluten-free diet

Diagnosis of Gluten Sensitivity:

Gluten sensitivity is often a diagnosis of exclusion, meaning that you have to rule-out celiac disease while still demonstrating a reaction to gluten and improvement in symptoms when the patient avoids gluten.

1. Blood tests: must be eating gluten regularly (I recommend at least 1 serving daily for at least 3-4 weeks) before testing

• Serum immunoglobulin A (IgA) must be normal (rule-out IgA deficiency)
• Deamidated gliadin peptide (DGP) IgA and IgG are considered more sensitive and specific than gliadin antibodies (1) especially if other tests are normal
• Endomysial antibodies (IgA) and/or tissue transglutaminase (tTG) IgA antibodies may be negative

2. Positive results from a gluten-free diet: sometimes this is the only proof a patient needs! I’ve seen patients improve significantly on a gluten-free diet and if that is the case, further testing may cause more harm than good.

What do I use in my practice?

I’ve used 3 different tests in my practice so far, but I haven’t settled on just one because they each have advantages and disadvantages.

1. CELIACSURE

This is an in-office test for tissue transglutaminase (tTG) only and can be completed with quick results in-office at a reasonable price.

The advantage is quick diagnosis using only a finger-prick while the patient is still eating gluten. The disadvantage is that tissue transglutaminase (tTG) antibodies may be negative while other antibodies (such as deamidated gliadin peptide (DGP)) are positive, so even with a negative result, further testing is indicated to really rule-out gluten sensitivity or celiac disease.

2. Gamma Dynacare Celiac Profile Panel

This is how I tested myself because it includes the combination of 4 tests that is currently considered to be the most comprehensive: total IgA, transglutaminase IgA, deamidated gliadin IgA, deamidated gliadin IgG.

The advantage is that it is most complete and highly accurate as long as the patient is eating gluten daily for 3-4 weeks before testing. None of these tests cover endomysial antibodies, but this test can be added onto the Gamma Dynacare testing at additional cost. The disadvantage is that this test is more expensive, involves a blood draw rather than finger-prick, and I have to send patients to a Gamma Dynacare lab location for the blood draw, which also involves a collection fee.

This is currently my test of choice because it minimizes the need for future testing, although the test below is also a great option.

3. Rocky Mountain Analytical Celiac Profile

I’ve recently ordered some of these test kits for in-office finger-prick blood collection that then needs to be sent away for results. This kit tests tissue transglutaminase, gliadin IgA, and gliadin IgG.

The advantage is an easier in-office finger-prick collection that covers 3 key tests at a lower price than the Gamma Dynacare testing. For most people this testing is sufficient and at a lower price without having to do a full blood draw at a lab. The disadvantage is that testing gliadin rather than deamidated gliadin is less sensitive and specific and this test does not include total IgA (which is helpful to rule-out IgA deficiency).

References:

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1808891/pdf/cei0134-0516.pdf