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Celiac & Other Gastrointestinal (GI) Diseases

Abdominal pain, chronic diarrhea, iron-deficiency anemia, and other malabsorption symptoms:1,2 These are just a few of many similar symptoms that can make differentiating between Gastrointestinal (GI) conditions difficult and frustrating for you and your patients. Such is the case with Celiac Disease (CD), Inflammatory Bowel Diseases (IBD) and Irritable Bowel Syndrome (IBS). Diagnosing these diseases can be particularly challenging because they often target the same organ, the bowel.1 Laboratory investigations can be used to diagnose patients with GI symptoms easier, potentially reducing time to diagnosis and therefore the risk of long-term complication for your patient.

Gastrointestinal Diseases

Differentiating between GI disorders?

IBS, GI cancers, CD and IBD can all present with varying patterns of similar GI symptoms:

CD (also called gluten-sensitive enteropathy or non-tropical sprue) is an autoimmune disorder of the small intestine that manifests itself when patients consume foods containing gluten.3

Take me to CD >

IBD are a group of chronic inflammatory disorders of the GI tract. Most notable among this group are Crohn’s Disease (CrD) and Ulcerative Colitis.4


IBS is a chronic, relapsing and often lifelong disorder with medically unexplained symptoms. IBS is the most common functional GI disorder. 5

GI cancer is the fourth most common cause of cancer-related death in the world, and it remains difficult to cure in Western countries, primarily because most patients present with advanced disease.6



Following your clinical history there are many investigations you can use to help diagnose patients with GI symptoms easier.
These include:

  • Serological investigations
  • Stool investigations
  • External imaging procedures
  • Endoscopic procedures
  • Biopsies

The following diagnostic algorithm serves as an example of best practice in the diagnosis of lower GI-conditions:3,7,8

Food Allergy
Celiac Disease

Algorithm recommended by Thermo Fisher Scientific, *adapted from Husby, et al 2012, Werkstetter et al., 2017, and World Health Organization, 2015.

The potential for GI cancer should prompt referral to secondary care in patients that present the following red flag symptoms:

  • Abdominal masses
  • A family history of ovarian cancer
  • Rectal masses
  • Anemia


  • Rectal bleeding
  • Unintentional and unexplained weight loss
  • A family history of bowel cancer
  • Aged >60 years change in bowel habit lasting >6 weeks9

Following your clinical history, in the case of recurrent lower-GI symptoms when you have no clinical suspicion of GI cancer, first line serological or stool based tests are used to rule out more serious conditions and/or determine the need for further investigations.10-13

Gluten-Related Disorders (GRDs): A summary

Even though CD is one of the most common lifelong autoimmune disorders in the world, correct diagnosis rates are surprisingly low.6 This can be attributed to CD’s atypical clinical presentation, as well as its shared characteristics with other GRDs.6

GRDs cover a broad spectrum of diseases triggered by gluten including CD non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) or wheat allergy. NCGS can be used to describe patients who may experience symptoms similar to CD because their bodies do not tolerate gluten. However, NCGS does not cause the same extreme bodily response and intestinal damage that CD does.7

Misdiagnosis when differentiating between GI disorders is common due to similar symptoms, especially as CD can also present with osteoporosis, malabsorption symptoms, sterility, and poliabortivity.8-11

When left untreated, patients with CD are at-risk for serious long-term complications, such as increased autoimmunity, osteoporosis, and even certain cancers.12-14


Allergy Testing

Valuable tools to aid In diagnosis

Differentiating between GI conditions, the symptoms of which are very similar, can be difficult and frustrating for both patients and healthcare professionals. However, serological testing can be used to help differentiate between GI conditions, potentially reducing the time to diagnosis.8,9,13,14

These tests can be used to help support the ruling-in or ruling-out of possible conditions, confirm the presence of inflammation, and help differentiate diseases.

Discover how antibody assays and calprotectin testing can aid in the diagnosis of GI disorders and why they are such a valuable tool for your practice.

  1. Pascual V, Dieli-Crimi R, López-Palacios N, et al. Inflammatory bowel disease and celiac disease: Overlaps and differences. World J Gastroenterol. 2014;20(17):4846-4856. 
  2. Celiac Disease Foundation. What is Celiac Disease? https://celiac.org/celiac-disease/understanding-celiac-disease-2/what-is-celiac-disease/. Accessed October 2017.
  3. Husby S, Koletzko S, Korponay-Szabó IR, et al. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition Guidelines for the Diagnosis of Coeliac Disease. J Pediatr Gastroenterol Nutr. 2012;54:136–160. 
  4. Crohn’s & Colitis Foundation of America.  Important Differences between IBD and IBS. http://www.crohnscolitisfoundation.org/assets/pdfs/ibd-and-irritable-bowel.pdf. Accessed October 2017.  
  5. Harkness EF, Harrington V, Hinder S, et al. GP perspectives of irritable bowel syndrome – an accepted illness, but management deviates from guidelines: a qualitative study. BMC Fam Pract. 2013;14: 92. 
  6. Picarelli A, Di Tola M, Borghini R, et al. The High Medical Cost of Celiac Disease Missed Diagnosis: Is it Cheaper to Suspect it in Time? Intern Med. 2014;4:155. 
  7. Sapone A, et al. Spectrum of gluten-related disorders: consensus on new nomenclature and classification. BMC Medicine. 2012, 10:13
  8. Jatla M, Verma R. Celiac disease: A comprehensive review and update. Introduction to a new series. Pract Gastroenterol. 2008;32(4):17 2008. 
  9. Van Assche G, Dignass A, Panes, et al. The second European evidence-based Consensus on the diagnosis and management of Crohn’s disease: Definitions and diagnosis. J Crohns Colitis. 2010;4:7-27.
  10. Beyond Celiac. Celiac Disease Symptom List. https://www.beyondceliac.org/celiac-disease/symptoms/. Accessed November 2017.
  11. Green PH. The many faces of celiac disease: clinical presentation of celiac disease in the adult population. Gastroenterology. 2005;128:S74-78. 
  12. Schuppan D, Zimmer KP. The Diagnosis and Treatment of Celiac Disease. Dtsch Arztebl Int. 2013;110(49):835–846.
  13. Lauret E, Rodrigo L. Celiac disease and autoimmune‐associated conditions. BioMed Research International. 2013;127589. 
  14. Green PHR, Stavros SN, Panagi SG, et al. Characteristics of adult celiac disease in the USA. results of a national survey. Am J Gastrol. 2001;96:126–131.