Gluten, Fecal, Quantitative

CPT: 83520
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Synonyms

  • Fecal, Gluten
  • Gliadin 33mer
  • Stool, Gluten

Expected Turnaround Time

4 - 6 days



Specimen Requirements


Specimen

Stool (unpreserved, random)


Volume

3 g


Minimum Volume

1 g


Container

Clean, screw-capped, plastic vial with no preservatives


Collection

Do not contaminate outside of container with specimen; do not overfill container. Loose/watery stools are acceptable. Ensure that no toilet tissue/sanitary materials are present in the submitted specimen.


Storage Instructions

Refrigerate.


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3


Causes for Rejection

Non-fecal sample received (eg, serum, plasma, urine); stool contaminated with urine; samples taken from diaper unless portion taken has not been in contact with diaper material; preserved stool received (eg, 10% formalin, merthiolate formalin, sodium acetate formalin, or polyvinyl alcohol)


Test Details


Use

This Gluten ELISA test is intended for the quantitative determination of Gliadin 33mer in stool samples. This test may be used for the following applications:

• Monitoring Celiac Disease (CD) and non-celiac gluten sensitivity (NCGS) patients for adherence to a gluten-free diet (GFD).

• Monitoring accidental gluten consumption due to mislabeling or food/product contamination.

• Assisting in the diagnosis of a true "refractory" CD that is not related to accidental gluten exposure.2,4


Limitations

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.


Methodology

Quantitative enzyme-linked immunosorbent assay (ELISA)


Reference Interval

<12 ng/mL


Additional Information

Celiac Disease (CD) is a serious, underdiagnosed autoimmune condition that is caused by an immune response to dietary gluten-containing products in individuals with a genetic predisposition to CD.1,2 It has been reported that in the United States, the cumulative incidence of CD is 1.8% and this number is likely to be underestimation.1,3 The only available treatment for CD is complete, lifelong avoidance of gluten consumption (known as a gluten-free diet, or GFD).1,2,4 However, strict compliance with a GFD is very challenging, and a significant subset of patients who are trying their best to adhere to a GFD are not relieved from symptoms and have persistent biopsy-detectable damage of the mucosal layer in their gastrointestinal tract.1,4 One study found that among patients on a strict GFD, 38% of biopsied patients still had intestinal damage.5 An analysis of data from a large registry of patients diagnosed with celiac disease revealed that 47% reported symptoms even with adherence to a strict GFD.6 More common than celiac disease, non-celiac gluten sensitivity (NCGS) is another condition involving an intolerance to gluten that improves on a GFD. NCGS is gaining attention among clinicians, but because there is no biomarker specific for NCGS, it is implicated when celiac disease, wheat allergy and other causes of symptoms have been ruled out.2,4,7 In a survey of the general population, 13% of participants self-reported as sensitive to gluten.7

One of the main reasons for GFD non-compliance is that there are many sources for gluten contamination that may cause accidental gluten consumption. While CD patients may be able to tightly control and avoid consumption of gluten-containing foods in the kitchen at home or in restaurants that use only gluten-free labeled foods, it is nearly impossible to control products that are mislabeled as "gluten-free."8 There currently is no widely available method to accurately detect and measure the amount of gluten present in consumable products such as food, medication, and supplements, and many products labeled as gluten-free may in fact contain gluten in amounts that are sufficient to trigger symptoms and mucosal damage in CD patients.9,10

While the intestinal biopsy is the "gold standard" for the detection of persistent mucosal damage, it would be more practical and cost-effective to be able to monitor patients for adherence to a GFD using non-invasive methods. However, currently utilized serological markers such as tTG IgA and EMA IgA are reported to have a sensitivity below 50% for the detection of persistent villous atrophy in patients on a GFD, and there is a need for a more accurate way of monitoring the non-response to a GFD.5,11 The detection of gluten in stool samples is reported to be a reliable alternate approach to monitoring adherence to a GFD, thus allowing for the direct measurement of the disease-triggering source in these patients.11 In a study of celiac patients on a GFD, among patients with persistent symptoms, 67% had detectable levels of gluten in their stools.11 Gluten in stool remains detectable for up to four days after consumption.11 In another study of patients endeavoring to adhere to a strict GFD, two-thirds were shown to have been exposed to gluten during the 10-day study period.12


Footnotes

1. Guandalini S, Assir A. Celiac disease: a review. JAMA Pediatr. 2014 Mar;168(3):272-278.24395055
2. Taylor AK, Lebwohl B, Snyder Cl, Green PHR. Celiac Disease. Adam MP, Ardinger HH, Pagon RA, et al, editors. In: GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993–2021.2008 Jul 3 [updated 2019 Jan 31].20301720
3. Balistreri WF. 5 Detection Strategies for Celiac Disease. Medscape Web site. https://www.medscape.com/viewarticle/899804. July 30, 2018. Accessed December 2021.
4. Rubin JE and Crowe SE. Celiac Disease. Ann Intern Med. 2020 Jan. 7;172(1):ITC1-ITC16.31905394
5. Silvester JA, Kurada S, Szwajcer A, Kelly CP, Leffler DA, Duerksen DR. Tests for Serum Transglutaminase and Endomysial Antibodies Do Not Detect Most Patients With Celiac Disease and Persistent Villous Atrophy on Gluten-free Diets: a Meta-analysis. Gastroenterology. 2017 Sep;153(3):689-701.e1.28545781
6. Chen K, Geller M, Leffler D, et al. Disease burden and quality of life impacts in patients with celiac disease on a gluten-free diet: an analysis of the iCureCeliac® registry. Poster presented at the American College of Gastroenterology (ACG) Virtual Meeting 2020, October 23-28, 2020.
7. Balistreri WF. Should We All Go Gluten-Free? Medscape Web site. https://www.medscape.com/viewarticle/857971. Feb 4, 2016. Accessed December 2021.
8. Forbes GM. Celiac Disease Patients Should No Longer Be Consuming Measurable Amounts of Gluten. Gastroenterology. 2020 Sep;159(3):1189.32439499
9. Bruins Slot ID, Bremer MGEG, van der Fels-Klerx I, Hamer RJ. Evaluating the Performance of Gluten ELISA Test Kits: The Numbers Do Not Tell the Tale. Cereal Chem. 2015;92(5):513-521.
10. The Celiac Disease Foundation Submits Comment to FDA on Draft Guidance Regarding Gluten in Medications. Celiac Disease Foundation Web site. https://celiac.org/about-the-foundation/featured-news/2018/02/celiac-disease-foundation-submits-comment-fda-draft-guidance-regarding-gluten-medications/. February 15, 2018. Accessed December 2021.
11. Comino I, Fernández-Bañares F, Esteve M, et al. Fecal Gluten Peptides Reveal Limitations of Serological Tests and Food Questionnaires for Monitoring Gluten-Free Diet in Celiac Disease Patients. Am J Gastroenterol. 2016 Oct;111(10):1456-1465.27644734
12. Silvester JA, Comino I, Kelly CP, Sousa C, Duerksen DR, Doggie Bag Study Group. Most Patients with Celiac Disease on Gluten-free Diets Consume Measurable Amounts of Gluten. Gastroenterology. 2020 Apr;158(5):1497-1499.e1.31866245

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
123027 Gluten, Fecal, Qn 100359-9 123028 Gluten, Fecal, Qn ng/mL 100359-9

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