Tissue Transglutaminase Antibody, IgA With Reflex to Endomysial Antibody, IgA by IFA
Also known as: EMA RFLX
Use
The presence of tissue transglutaminase (tTG) IgA antibody is associated with gluten-sensitive enteropathies such as celiac disease and dermatitis herpetiformis. Positive results should be confirmed with a small intestinal biopsy to establish a celiac disease diagnosis. High concentrations of tTG IgA antibodies correlate with duodenal biopsies consistent with celiac disease. Additional testing for endomysial (EMA) IgA concentrations is recommended for certain antibody concentration ranges to improve the positive predictive value for disease. Monitoring antibody concentration can indicate a response to a gluten-free diet.
Special Instructions
All serologic tests for celiac disease should be performed while the patient is on a gluten-containing diet. Reflexive panel testing is preferred to screen for celiac disease. This test may indicate early disease or false positivity in certain cases, requiring close clinical correlation with continued testing, especially in patients with a family history or increased risk for celiac disease.
Limitations
The test is most sensitive and specific in individuals who produce sufficient total IgA. In IgA-deficient individuals, alternative tests such as tTG IgG and deamidated gliadin peptide (DGP) IgG antibody testing are recommended. False positivity may occur, necessitating further clinical correlation. Intestinal biopsy remains a definitive method for diagnosis in certain cases. Antibody titers may vary based on patient response to a gluten-free diet.
New York Approved
Methodology
Other
Biomarkers
LOINC Codes
- 46128-5
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Serum separator tube (SST)
Collection Instructions
Separate serum from cells ASAP or within 2 hours of collection. Transfer to an ARUP standard transport tube.
Storage Instructions
Refrigerated.
Causes for Rejection
Contaminated, grossly hemolyzed, grossly icteric, or grossly lipemic.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 1 week |
| Frozen | 30 days (avoid freeze/thaw cycles) |