Tissue Transglutaminase (tTG) Antibody, IgA with Reflex to Endomysial Antibody, IgA by IFA
Celiac disease: Do not use in IgA-deficient individuals; acceptable reflex screening test for celiac disease. However, Celiac Disease Reflexive Cascade (2008114) or Tissue Transglutaminase (tTG) Antibody, IgA (0097709) assay is the preferred screening test.
Immunobullous diseases: Use along with pemphigoid and pemphigus panel tests and epidermal IgA tTG antibody (2010902), or with epithelial skin antibody and epidermal IgA tTg antibody (2010902) tests to initially diagnose and discriminate among the immunobullous skin diseases in patients suspected or known to have any type of immunobullous disease.
Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody
Serum separator tube.
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)
Urine or plasma. Contaminated, heat-inactivated, or severely hemolyzed specimens.
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid freeze/thaw cycles)
Tissue Transglutaminase Antibody, IgA: Presence of the tissue transglutaminase (tTG) IgA antibody is associated with gluten-sensitive enteropathies such as celiac disease and dermatitis herpetiformis. tTG IgA antibody concentrations greater than 10 U/mL usually correlate with results of duodenal biopsies consistent with a diagnosis of celiac disease. For antibody concentrations greater than 3 U/mL but less than 41 U/mL, additional testing for endomysial (EMA) IgA concentrations may improve the positive predictive value for disease.
Endomysial Antibody, IgA by IFA: The endomysial antigen has been identified as the protein cross-linking enzyme known as tissue transglutaminase.
Testing for tTG IgA antibodies is recommended as an initial screen to identify patients at risk for celiac disease, and in whom duodenal biopsy should be performed to confirm disease.
Some patients may have positive tTG IgA but negative EMA IgA and/or deamidated gliadin peptide (DGP) IgA results, which may be associated with false positivity or may indicate early disease. Close clinical correlation with continued testing may be indicated in patients with a family history of or who are at increased risk for celiac disease. A positive serology but normal biopsy may also indicate a gluten-free diet (GFD) prior to testing, latent disease, or early enteropathy. Re-challenge with a gluten diet may be recommended if GFD had been initiated prior to subsequent testing. In the case of latent or early disease, HLA DQ2 and DQ8 testing may be necessary to determine risk for disease.
For patients with a high degree of suspicion for celiac disease and who test negative for tTG, EMA, and/or DGP IgA tests, selective IgA-deficiency should be considered and testing for tTG, EMA, and/or DGP IgG antibodies performed.
If serology is negative and suspicion of celiac disease is strong, intestinal biopsy may be warranted. Biopsy is particularly important for patients with diarrhea, steatorrhea, weight loss, failure to thrive, or with inherited genetic deficiencies such as Down or Turner syndromes.
Specimen is screened using tissue transglutaminase IgA by ELISA. If tTG IgA is 4 U/mL or greater, then EMA IgA by IFA testing will be added. Additional charges apply. All EMA IgA by IFA testing is titered to endpoint.
83516; if reflexed, add 86256
|Component Test Code*||Component Chart Name||LOINC|
|0097709||Tissue Transglutaminase (tTG) Ab, IgA||46128-5|
- Anti-Endomysial Antibody
- Anti-tissue Transglutaminase Antibody
- Antiendomysial Antibody
- Celiac Disease
- Gluten Sensitivity
- Gluten-Sensitive Enteropathy Tests
- Tissue Transglutaminase Ab IgA
- tTG IgA