Tissue Transglutaminase (tTG) Antibody, IgA with Reflex to Endomysial Antibody, IgA by IFA
0050734
Ordering Recommendation
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.
Submit With Order
Mnemonic
EMA R
Methodology
Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody
Performed
Sun-Sat
Reported
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
 
Collect
Serum separator tube.  
Specimen Preparation
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)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
Urine or plasma. Contaminated, heat-inactivated, or severely hemolyzed specimens.  
Remarks
 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid freeze/thaw cycles)  
Reference Interval
Test Number Components Reference Interval
0097709Tissue Transglutaminase (tTG) Antibody, IgA 19 Units or less: Negative
20-​30 Units: Weak Positive
31 Units or greater: Moderate to Strong Positive
0050736Endomysial Antibody, IgA by IFA Less than 1:10
Interpretive Data
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 or equal to 100 Units usually correlate with results of duodenal biopsies consistent with a diagnosis of celiac disease. For antibody concentrations greater than 20 Units but less than 100 Units, 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.
Note
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 20 units or greater, then EMA IgA by IFA testing will be added. Additional charges apply. All EMA IgA by IFA testing is titered to endpoint.
CPT Code(s)
83516; if reflexed, add 86256
Components
Component Test Code*Component Chart Name
0097709Tissue Transglutaminase (tTG) Ab, IgA
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Cross References
  • Anti-EMA
  • Anti-Endomysial
  • Anti-Endomysial Antibody
  • Anti-tissue Transglutaminase Antibody
  • Antiendomysial
  • Antiendomysial Antibody
  • Celiac Disease
  • EMA
  • Gluten Sensitivity
  • Gluten-Sensitive Enteropathy Tests
  • Tissue Transglutaminase Ab IgA
  • tTG IgA