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Gastrointestinal (GI) Diseases

Differentiating between GI conditions, including Celiac Disease (CD) and Inflammatory Bowel Disease (IBD) can be difficult for both patients and healthcare professionals. Patients often live years with untreated symptoms, which often overlap with other GI and autoimmune diseases, before receiving the correct diagnosis.1,2 Healthcare professionals may be left feeling frustrated. Laboratory testing can help healthcare providers differentiate between certain GI conditions, potentially reducing the time to accurate diagnosis and effective treatment.3-4

Diagnosing celiac disease

Celiac disease is an under-diagnosed, under-managed condition.5 On average, it takes 11 years from symptom onset for celiac disease to be diagnosed.2 Complicating diagnosis are several factors, including the presentation of relatively nondescript symptoms and the onset of disease at a time during a patient’s life when he or she may be experiencing similar symptoms due to other causes.5

Serological testing can help differentiate this disease and provide an accurate, expedited diagnosis. It may help to consider testing when there is presentation of gastrointestinal symptoms or a new diagnosis for a condition that increases the risk for having celiac disease.6 Expediting the time to diagnosis can help alleviate symptoms and improve quality of life.6

Serological testing for celiac disease

International classification criteria advocates for serologic testing to help aid in the diagnosis of celiac disease. The European Society for Pediatric Gastroenterology, Hepatology and Nutrition has published guidelines for the diagnosis of celiac disease for children or adolescents with otherwise unexplained symptoms and signs suggestive of CD. 7 It states that children should be tested for:

  • Immunoglobulin A (IgA) transglutaminase (tTG) and total IgA, as the first choice
  • Deamidated Gliadin (DGP) IgG, tTG IgG, or IgG endomysial antibodies (EMA) if IgA is deficient

The National Institute for Health and Care Excellence encourages young people and adults to be tested for:8

  • tTG IgA and total IgA as the first choice
  • IgA EMA if tTG IgA is weakly positive
  • IgG deamidated gliadin peptide, tTG IgG, or IgG EMA if IgA is deficient
     

Villata et al. compared the diagnostic accuracy of 9 IgG anti- tissue transglutaminase, 1 IgG anti-gliadin and 1 IgG anti- deamidated gliadin peptide antibody assays. The results demonstrated the EliA Celikey IgG (tTG IgG) assay is specific for CD in IgA deficiency. Also, EliA Gliadin DP IgG test has high diagnostic sensitivity not only in IgA competent, but also in IgA deficient CD patients.9 Selective IgA deficiency is more common in celiac disease patients (1 in 40) than in the general population (1 in 400). IgA deficiency should be considered if tissue transglutaminase IgA levels are undetectable.10

EliA Celikey IgA (tissue transglutaminase IgA)11

Sample material: Serum, plasma (EDTA, citrate)

 


Reference Values

 Measuring range: 0.1–128 U/ml  
 Value  Classification 
 <7 U/ml  Negative 
 7–10 U/ml  Equivocal 
 >10 U/ml  Positive

Download Directions for Use >

EliA Celikey IgG (tissue transglutaminase IgG)12

Sample material: Serum, plasma (EDTA, citrate)

Method: EliA IgG, found on the instrument Phadia 250 


Reference Values

 Measuring range: 0.6–600 U/ml  
 Value  Classification 
 <7 U/ml  Negative 
 7–10 U/ml  Equivocal 
 >10 U/ml  Positive

Download Directions for Use >

EliA GliadinDP IgG13

Sample material: Serum, plasma (EDTA, citrate, heparin)


Reference Values

 Measuring range: 0.4–302 U/ml  
 Value  Classification 
 <7 U/ml  Negative 
 7–10 U/ml  Equivocal 
 >10 U/ml  Positive

Download Directions for Use >

EliA GliadinDP IgA14

Sample material: Serum, plasma (EDTA, citrate, heparin)


Reference Values

 Measuring range: 0.2–213 U/ml  
 Value  Classification 
 <7 U/ml  Negative 
 7–10 U/ml  Equivocal 
 >10 U/ml  Positive

Download Directions for Use >


EliA Gliadin DP IgA and IgG are highly sensitive in young children; children below 18 months may have insufficient tTG antibodies for a reliable diagnosis.15

 

Reference values apply to all ages. Reference values, coating, dilution and sample material have been taken from respective Phadia™ 250 instrument Directions for Use. These data are intended as a guide and should be treated accordingly.  

If you have any questions or uncertainty please contact us >

Allergy Testing

Conditions & Diseases

Understand allergic and autoimmune diseases.
 

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References
  1. Waugh N, Cummins E, Royle P, et al. Faecal calprotectin testing for differentiating amongst inflammatory and non-inflammatory bowel diseases: systematic review and economic evaluation. Health Technology Assessment. 2013;17:1-211. 
  2. Green P, Stavropoulos S, Panagi S, et al. Characteristics of adult celiac disease in the USA: results of a national survey. Am J Gastroenterol. 2001;96 126-31. 
  3. Van Assche G, Dignass A, Panes J, 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. 
  4. National Health Service. Irritable bowel syndrome (IBS). Diagnosis. https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/diagnosis/#ruling-out-other-conditions. Accessed November 2017. 
  5. Shah S, Leffler D. Celiac disease: an underappreciated issue in women’s health. Womens Health (Lond Engl). 2010;6(5):753-766. 
  6. Samasca G, Sur G, Lupan I. Gluten-free diet and the quality of life in celiac disease. Gastroenterol Hepatol Bed Bench. 2014;7(3):139-143.
  7. 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;54:136–60.
  8. National Institute for Health and Care Excellence. Coeliac disease: recognition, assessment and management. https://www.nice.org.uk/guidance/ng20/resources/coeliac-disease-recognition-assessment-and-management-pdf-1837325178565. Accessed November 2017. 
  9. Villalta D, Alessio MG, Tampoia M, et al. Testing for IgG class antibodies in celiac disease patients with selective IgA deficiency: A comparison of the diagnostic accuracy of 9 IgG anti-tissue transglutamine, 1 IgG anti-gliadin and 1 IgG anti-deaminated gliadin peptide antibody assays. Clinica Chimica Acta. 2007;382(1–2):95-99. 
  10. Rubio-Tapia A, Hill ID, Kelly CP, et al. ACG Clinical Guidelines: Diagnosis and Management of Celiac Disease. Am J Gastroenterol. 2013;108:656-676.  
  11. Phadia™ EliA™ Celikey IgA Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
  12. EliA Celikey IgG Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
  13. EliA GliadinDP IgG Directions for Use for the Phadia 250 Laboratory System. Issued April 2017.
  14. EliA GliadinDP IgA Directions for Use for the Phadia 250 Laboratory System. Issued April 2017.
  15. Lagerqvist C, et al. Antigliadin immunoglobulin A best in finding celiac disease in children younger than 18 months of age. J Pediatr Gastroenterol. 2008; 47(4): 428-435.