To diagnose celiac disease, blood tests (serology testing or genetic testing) and an endoscopy are currently the methods doctors use to test for the disease. The blood test and biopsy are the only way to determine for certain whether a person has celiac disease.
Celiac disease is an autoimmune disorder in which the body mistakenly reacts to gluten, a protein found in wheat, barley and rye, as if it were a poison. It affects as many as one in 141 people, although most have not been diagnosed. When someone with celiac consumes gluten, the immune system reacts by destroying the part of the small intestine that absorbs vital nutrients. This malabsorption can lead to serious illness. Click here to learn more about celiac disease.
A definitive blood test and biopsy can only be performed when a patient is eating gluten. Test results for someone following a gluten-free diet for any length of time are rendered inaccurate. For more information on eating gluten to test for celiac disease, click here.
Blood tests
Serology testing is blood work that looks at antibodies in the blood, because people with celiac disease have higher levels of certain antibodies. The antibodies are produced by the immune system when a person with celiac disease is eating gluten, since the body sees gluten as a threat. The gold standard test for celiac disease is the anti-tissue transglutaminase (tTG-IgA) test. If this test is positive, it’s recommended that an upper endoscopy, in which six duodenal biopsies are taken, be done.
Genetic testing can be used to rule out celiac disease, since it is a genetic condition. Though genetic testing can’t tell you if you have celiac disease, it can show whether you have one of the two specific genes typically needed to develop celiac disease. If you have celiac disease, your close blood relatives should be tested for celiac disease. This is true even if they do not have symptoms, as celiac disease is sometimes asymptomatic.
Those who have celiac disease virtually always have the DQ2 and DQ8 genes, and genes are not affected by the diet. If you don’t have the genes, it’s nearly certain you don’t have celiac disease. If you do have the genes, it does not mean you do have celiac disease, only that the potential exits.
Endoscopy and intestinal biopsy
Those with evidence of celiac undergo an endoscopy to confirm the diagnosis. During an endoscopy, the patient is put under anesthesia and doctors insert a tube through the mouth and into the small intestine to biopsy a few samples of the intestinal lining. After the procedure, doctors might have some idea how likely celiac is based on what they’ve observed, but they cannot confirm the diagnosis until the biopsy sample is analyzed by a pathologist. That procedure usually takes a few days.
Additional methods of diagnosing celiac disease are being studied. One of these is a PillCam, which is ingested by a patient and explores the small intestine for a celiac diagnosis. Combined with computer technology, it can diagnose the disease without an invasive procedure and with greater accuracy.
The importance of diagnosis
Untreated celiac disease presents health risks. A study from Columbia University found that the intestinal damage brings a four times greater risk of developing a type of lymphoma, or blood cancer. Celiac disease is also linked to osteoporosis, thyroid problems, type 1 diabetes and malabsorption of nutrients.
Accurate diagnosis provides real benefits for individuals and for the celiac disease population at large. Currently, the only treatment for celiac disease is a gluten-free diet. When gluten is taken out of the diet, the small intestine heals and a return to full health can be expected. These guidelines, compiled by a registered dietitian nutritionist, are intended to provide a good start down the road to a healthy, happy gluten-free life.
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