Tissue Transglutaminase Antibody, IgA
Also known as: TTG A
Use
The presence of tissue transglutaminase IgA antibody is associated with gluten-sensitive enteropathies such as celiac disease and dermatitis herpetiformis. This test is useful for evaluating suspected celiac disease in IgA-competent individuals and may aid in monitoring therapeutic response to a gluten-free diet in confirmed celiac disease cases. Positive test results should be confirmed with a small intestinal biopsy for a definitive diagnosis.
Special Instructions
In individuals with sufficient total IgA production, the tissue transglutaminase IgA test is the most sensitive and specific serologic test for diagnosing celiac disease. For those who are IgA deficient, alternative tests such as tTG IgG and deamidated gliadin peptide IgG are recommended. Testing should be conducted while the patient maintains a gluten-containing diet to ensure accurate serology. A reflexive panel is preferred for screening celiac disease.
Limitations
This test is least effective in individuals with IgA deficiency and for those not consuming a gluten-containing diet at the time of testing. Additionally, patients with dermatitis herpetiformis may exhibit uneven antibody patterns, and concurrent CD reflexive panel and immunobullous disease panel testing are preferred for a comprehensive assessment. Normalization of antibody titers upon following a gluten-free diet varies by patient case, and negative serology may necessitate an intestinal biopsy if celiac disease suspicion persists.
New York Approved
Methodology
Other
Biomarkers
LOINC Codes
- 46128-5
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.0 mL
Minimum Volume
0.5 mL
Container
ARUP standard transport tube
Collection Instructions
Separate serum from cells ASAP or within 2 hours of collection.
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 |