Celiac disease tests are primarily used to help diagnose celiac disease. They are usually ordered on patients with symptoms suggesting celiac disease, including anemia and abdominal pain.

Sometimes celiac testing is ordered to screen for asymptomatic celiac disease in people who have close relatives with celiac disease (about 10% of these patients have or will develop celiac disease) and/or in those who have other autoimmune diseases.

Other tests to help determine the severity of the disease and the extent of a patient’s malnutrition, malabsorption, and the involvement of other organs might include:

CBC (complete blood count) to look for anemia

ESR (erythrocyte sedimentation rate) to evaluate inflammation

CRP (C-Reactive protein) to evaluate inflammation

CMP (comprehensive metabolic panel) to determine electrolyte, protein, and calcium levels, and to verify the status of the kidney and liver

Vitamin D, E, and B12 to measure vitamin deficiencies

Stool fat, to help evaluate malabsorption

Since those with celiac disease may also experience conditions such as lactose intolerance, celiac tests may be done in conjunction with other intolerance and allergy testing. Anti-tTG, AGA, and/or EMA tests may be ordered at intervals on patients who have been diagnosed with celiac disease to monitor compliance with a gluten-free diet and to help evaluate the effectiveness of treatment; antibody levels should fall when gluten is removed from the diet.

Celiac disease tests are ordered when someone has symptoms suggesting celiac disease, malnutrition, and/or malabsorption - such as diarrhea, abdominal pain, weakness, fatigue, weight loss, and joint pain. They may be ordered as part of an investigation of anemia, osteoporosis, infertility, or seizures (certain types are linked to celiac disease). In children, celiac disease tests may be ordered when a child exhibits gastrointestinal symptoms, delayed development, short stature and/or a failure to thrive.

Autoantibody levels should initially be ordered when a patient still has gluten in their diet. Positive or indeterminate results will then be confirmed with a biopsy. One or more antibody tests may be ordered when a patient with celiac disease has been on a gluten-free diet for a period of time. This is done to verify that antibody levels have decreased and to verify that the diet has been effective in relieving symptoms and reversing the intestinal lining damage (this is sometimes still confirmed with a second biopsy). When a patient’s symptoms have not subsided, celiac disease tests may be ordered to check for dietary compliance and to help the doctor and patient look for either hidden gluten in the patient’s diet or for other reasons for their unrelieved symptoms. Asymptomatic people may be tested if they have a close relative with celiac disease, but celiac disease testing is not recommended at this time as a screen for the general population.

Some celiac disease tests and possible results include:

Anti-tTG antibodies, IgA	Total IgA	Anti-tTG antibodies, IgG	Anti-Gliadin antibodies (AGA), IgG	Diagnosis
+	+			Presumptive celiac disease
-	+	-	-	Symptoms not likely due to celiac disease
-	-	+	+	Possible celiac disease, false negative anti-tTG, IgA due to total IgA deficiency

Positive and indeterminate celiac disease tests are usually followed by an intestinal biopsy. A biopsy is used to make a definitive diagnosis of celiac disease.

If a patient has been diagnosed with celiac disease and eliminates gluten from his diet, then the autoantibody levels should fall. If they do not fall and the symptoms do not diminish, then there may either be hidden forms of gluten in the diet that have not been eliminated (gluten is often found in unexpected places, from salad dressings to cough syrup to the adhesive used on envelopes) or the patient may have one of the rare forms of celiac disease that does not respond to dietary changes. When celiac disease tests are used to monitor progress, rising levels of autoantibodies indicate some form of noncompliance with a gluten-free diet.

If the person being tested has not consumed any gluten for several weeks prior to testing, then celiac disease tests may be negative (although this may require many months of gluten-free diet). If the doctor still suspects celiac disease, she may do a gluten challenge – have the patient introduce gluten into his diet for several weeks or months to see if the symptoms return. At that time, celiac tests may be repeated or a biopsy may be done to check for villous atrophy (damage to the villi in the intestine).

Although celiac disease is relatively common, about 1 in 133 people in the U.S. are thought to be affected; most people who have the disease are not aware of it. This is partly due to the fact that the symptoms are variable -- they may be mild or even absent, even when intestinal damage is present on biopsied tissue. Since these symptoms may also be due to a variety of other conditions, a diagnosis of celiac disease may be missed or delayed -- sometimes for years.