In honor of May Celiac Disease Awareness Month, Laboratory Corporation of America® Holdings (LabCorp®) (NYSE: LH) is proud to team with Celiac Disease Foundation. LabCorp is dedicated to raising awareness of celiac disease and to helping more people reach a diagnosis. LabCorp’s comprehensive celiac services program includes cost effective antibody testing profiles and HLA DQA/DQB genotyping with genetic risk assessment and expert celiac genetic consultation. In addition to extensive experience in celiac testing, LabCorp also offers the convenience of a wide network of managed care plans and patient service centers nationwide. LabCorp will be exhibiting at the upcoming CDF National Conference on June 7/8 and presenting about celiac testing and its critical role on the path to celiac diagnosis, family risk assessment, treatment and management.
Celiac disease is an autoimmune disorder that can occur in genetically predisposed people where the ingestion of gluten leads to inflammation and damage in the small intestine. Gluten is a protein found in wheat, barley, and rye. The disease is systemic and can include gastrointestinal symptoms and/or multiple, highly variable non-gastrointestinal symptoms. Once thought to be a rare malabsorption syndrome in children, celiac disease is actually one of the world’s most common genetic autoimmune disorders, affecting 1% of the population, including children and adults. The average lifetime risk of developing celiac disease is approximately 1%. If you have a parent, sibling or child with celiac disease your lifetime risk is in the range of 10-40%, with the highest risk for siblings who share the same genetic susceptibility as a patient with celiac disease.
Celiac Disease is Underdiagnosed
Diagnosing celiac disease has proven to be a challenge. As many as 300 symptoms are associated with this disease, and many people with celiac disease exhibit no outward symptoms at all. Coupled with celiac disease being considered rare by many physicians, the variability of symptoms results in an undiagnosed rate of approximately 80% in the United States. This means that 2.5 million Americans have celiac disease and don’t know it. Celiac disease is often misdiagnosed as intestinal bowel syndrome. The average time between onset of symptoms and diagnosis is 11 years. Awareness of celiac disease is increasing, but there is a long way to go!
Celiac disease increases risk for other autoimmune disorders (e.g. diabetes and autoimmune thryroiditis), various cancers, and other conditions such as osteoporosis, infertility, and vitamin deficiencies, which makes diagnosing and treating celiac disease all the more crucial for the health of those affected.
Symptoms of Celiac Disease
Celiac Disease Foundation has developed a Symptoms Checklist, which will help you document symptoms and associated conditions to share with your doctor to determine if you need screening for celiac disease or other disorders including wheat allergy and non-celiac gluten sensitivity.
Classic symptoms of celiac are gastrointestinal, and although diarrhea is the most common symptom, fewer than 50% of patients suffer from this condition. Many symptoms are secondary to malabsorption, and widely variable additional symptoms may include a characteristic rash, neurologic effects, cardiomyopathy, and dental enamel changes, to name a few. Anemia is the only symptom in 8% of patients with celiac, and osteoporosis in men is a red flag. Numerous autoimmune disorders are associated with celiac disease as a secondary development.
Silent Celiac Disease: Celiac disease can be present without symptoms, although celiac antibodies are present and the gut has damage. Testing asymptomatic first degree relatives of patients with celiac disease can identify silent celiac disease, which is beneficial because treatment with the gluten-free diet may decrease risk for secondary autoimmune diseases. Celiac HLA testing is useful in relatives to identify those at risk for developing celiac disease.
Treating Celiac Disease
Currently the only treatment for celiac disease is a strict, life-long, gluten-free diet. Once on a gluten-free diet, most people experience symptom relief and the damage done to their intestines heals after a certain period of time; therefore diagnosis is crucial. See “Key Books” below for references regarding the gluten-free diet.
Diagnosing Celiac Disease
Celiac Antibody Testing and Small Bowel Biopsy
Screening for celiac disease is by celiac antibody (serologic) testing. Antibodies develop against gut proteins (a key one is called tissue transglutaminase, or tTG) during active celiac disease, and if these antibodies are detected, it is highly likely that you have celiac disease. Confirmation of celiac diagnosis by a small bowel biopsy is usually recommended. New guidelines from Europe propose that the biopsy may not be necessary if antibody results are strongly positive and there is an HLA-DQ2 or DQ8-positive genotype, typical symptoms of celiac, and response to the gluten-free diet. These have not been widely adopted in the United States, but are followed by some physicians on a case-by-case basis.
Being on gluten is important for antibody testing and biopsy: The antibody tests and the biopsy require you to be on a diet that includes gluten for the last 1-3 months for the tests to be accurate. If you are already on a gluten-free diet and want to get tested, you will have to go on a gluten challenge with ingestion of gluten for 1-3 months. For that reason, Celiac Disease Foundation’s Medical Advisory Board suggests that before starting a gluten-free diet, you should be screened for celiac disease and other disorders such as wheat allergy and non-celiac gluten sensitivity, which have different risks and implications.
Celiac Genetic Testing (Celiac HLA DQA/DQB Genotyping)
For celiac to develop, combined proteins called DQ2 or DQ8 need to be present in the immune system. Testing detects specific variations in genes called HLA-DQA and HLA-DQB that code for DQ2 or DQ8. A negative result rules out the possibility of celiac disease, which is very useful in the diagnostic work-up of symptoms. It is important to note that although 30% of the population carries these gene variations, only about 3% of this group will develop celiac disease. However, knowing that you do not carry the predisposing genes will eliminate the need for further celiac antibody screening.
Celiac HLA testing is useful to rule out the possibility of developing celiac disease in these circumstances:
- When on a gluten-free diet
- When antibody or biopsy results are ambiguous
- Evaluating risk in asymptomatic relatives
- Patients in higher risk groups (eg. Type I diabetes, Crohn’s disease, autoimmune thyroid disease)
Finding a Doctor Who Treats Celiac Disease and Gluten-related Disorders
If you need help finding a doctor who treats celiac disease and gluten-related disorders, Celiac Disease Foundation’s Healthcare Practitioner Directory offers listings in your local area.
LabCorp’s Celiac Disease Testing Services
LabCorp’s celiac program includes:
- a comprehensive menu of celiac antibody (serological) tests, including profiles with reflexes,
- HLA-DQA/DQB Genotyping including genetic risk assessment and availability of buccal swab testing as an alternative to blood, and
- celiac consultation.
Celiac Consultation
LabCorp’s celiac expertise extends beyond tests to include consultative services. LabCorp’s scientific staff – including Dr. Annette Taylor, a geneticist and recognized leader in the celiac field – can provide client consultations and are readily available to answer questions on test selection and results.
Key Tests from LabCorp’s menu
- 167082 Celiac Disease HLA DQ Association
- 165142 Celiac Disease Profile (tTG/EMA, total IgA) with Reflex
(tTG-IgA, EMA-IgA, total IgA, with reflex to tTG-IgG if total IgA is decreased) - 341142 Celiac Disease Complete Profile (tTG/DGP)
(tTG-IgA and IgG, DGP-IgA and IgG, total IgA) - 165118 Celiac Disease Antibody Screen (tTG/DGP) with Reflex
(tTG-IgA, DGP-IgA, total IgA, with reflex to EMA-IgA if weak positive tTG-IgA) - 165126 Celiac Disease Comprehensive Antibody Profile
(tTG/DGP/EMA, total IgA)
(if all tests are desired simultaneously) - 164125 Gluten Sensitivity Screen with Reflex
(tTG-IgA/G, DGP-IgA/G, if neg reflex to Gliadin-IgA, if neg reflex to wheat IgE)
Additional profiles are also available with different combinations of antibody tests. See LabCorp.com/ Test Menu for more information.
For more information about celiac HLA testing or for a celiac genetic consultation, call 800-533-1037.
Other Resources
- Celiac Disease Foundation: www.celiac.org
- Celiac Disease Center at University of Columbia Medical Center: http://www.celiacdiseasecenter.columbia.edu/
- University of Chicago Celiac Disease Center: http://www.cureceliacdisease.org/
Key Books
- Celiac Disease: A Hidden Epidemic. Revised and Updated Edition, 2010; Peter HR Green and Rory Jones; HarperCollins Publishers
- Clinical Guide to Gluten-Related Disorders. Alessio Fasano, MD ed.; NASPGHAN Foundation; 2014 by Lippincott Williams & Wilkins, Philadelphia PA
- Gluten-Free, Hassle Free: A Simple, Sane, Dietician-Approved Program for Eating Your Way Back to Health. Second Edition. Marlisa Brown MS, RD, CDE. 2014 demosHealth, NY.
- Gluten-Free Grocery Shopping Guide 2014-2015 Edition. Mara Matison and Dainis Matison; www.ceceliaMarketplace.com
- Gluten-Free Kids: Raising Happy, Healthy Children with Celiac Disease, Autism and other Conditions. Danna Korn; 2010 revised edition; Woodbine House, NY
Key Articles
- Green PHR, Cellier C. Celiac Disease. N Engl J Med 2007;357:1731-1743
- Husby S et al. for the ESPGHAN Working Group on Coeliac Disease Diagnosis, on behalf of the ESPGHAN Gastroenterology Committee. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition Guideline for the Diagnosis of Coeliac Disease. JPGN 2012;54:136-160.
- Sapone A et al. Spectrum of gluten-related disorders: consensus on new nomenclature and classification. BioMed Central Medicine 10:13 1-12 http://www.biomedcentral.com/1741-7015/10/13
- Snyder CL et al. Celiac Disease. GeneReviews 2008;1-27. www.ncbi.nlm.nih.gov/books/NBK1727/
- Pagon RA et al. eds. Seattle (WA):University of Washington, Seattle 1993-2014.
Dr. Annette Taylor, contributor – in collaboration with Marilyn Geller, Celiac Disease Foundation