Once a healthcare provider suspects Celiac, the following methods of
diagnosis are most likely to occur:
A Celiac Panel, according to the University of Maryland Center for Celiac Research, includes:
- tTG-IgA or tissue transglutaminase-IgA
- AGA-IgG or Antigliadin IgG
- AGA-IgA or Antigliadin IGA
- Total Serum IGA ( immunoglobulin level)
The Celiac Center at Beth Israel Deaconess Medical Center uses the DGP (anti-Deamidated Gliadin Peptide) in place of the anti-Gliadin antibody test (AGA), if there is a known IgA deficiency, in addition to one or more of the tests noted above.
(note: you do not need to see a specialist for the blood tests, your PCP can arrange it.)
If tests are positive (elevated levels) this suggests Celiac is present. Elevated AGA alone can also indicate a wheat allergy, which is different from Celiac. (Note: 10% of people may have a “negative” blood test and still have Celiac. One reason for this could be an IgA deficiency, which could render a negative result, even though you still have Celiac). If symptoms persist, consider being tested again, especially if a family member has Celiac, and be sure to rule out having a selective IgA Deficiency. See note about regarding DGP test for those with IgA deficiency)
Next, to aid in the diagnosis, a small intestinal bowel biopsy* will, in most cases, be performed, where an endoscope is passed through the mouth into the small intestine to look for abnormalities such as inflammation and damage to the villi. Once on a gluten-free diet, the absence of symptoms combined with the intestinal biopsy, would confirm a diagnosis of Celiac. A repeat biopsy may occur once the individual has been on a gluten-free diet for a period of time, to check for intestinal healing. A biopsy may be recommended even if the blood test is negative, under certain conditions.
*the small intestinal biopsy had always been considered the “gold standard” in a final diagnosis of Celiac, until recently. According to Dr. Alessio Fasano, MD, director of the Center for Celiac Research at the University of Maryland School of Medicine, it is being considered whether the biopsy would be necessary for a diagnosis if the person fulfilled the majority of certain criteria (i.e. symptoms, antibodies, genes, improvement from GF diet). To date, the small intestinal biopsy is still considered the “gold standard”, but this may change in the future. Here is a recent study relating to this: http://www.biomedcentral.com/1471-230X/13/19
Important to note: A self-diagnosis of Celiac, and start of a gluten-free diet, is strongly discouraged. Gluten must be present in the body at the time of the blood test and biopsy, otherwise the test results could be unreliable.
Do not delay your diagnosis. If you suspect you have Celiac, make an appointment with your primary care physician or gastroenterologist. (See Resources for a list of gastroenterologists in your area).
At-Home Celiac Test
There is a Celiac Test available which you can use in the convenience of your home. It is called the BIOCARD Celiac Test, distributed by 2G Pharma Inc., Ontario. Keep in mind it should only be used as an aid in providing an immediate diagnosis (within 10 minutes), and you should confirm a diagnosis with a medical doctor, BEFORE commencing a gluten-free diet. See our Store/Test Kits.
Suggested reading: Article from University of Chicago Celiac Disease Center (Jan. 2012 Newsletter) “Evolving Diagnostic Criteria for Celiac Disease” http://www.cureceliacdisease.org/wp-content/uploads/2012/01/CdC_Newsletter_0112_v4-link.pdf
