Tissue Transglutaminase Antibody (IgA)
TTGA, TTG IgA, Tissue Transglutaminase Antibody, IgA
Test Codes
EPIC: LAB7230, Beaker: TTGAB
Department
Immunology
Specimen Collection Criteria
Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)
Physician Office/Draw Specimen Preparation
Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Minimum Serum: 0.5 mL)
Preparation for Courier Transport
Transport: Centrifuged collection tube, refrigerated (2-8 °C or 36-46 °F). (Minimum Serum: 0.5 mL)
Rejection Criteria
- Plasma specimens.
- Severely hemolyzed, lipemic or icteric specimens.
In-Lab Processing
Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Room temperature is acceptable for a maximum of two hours. (Minimum: 0.5 mL)
Storage
Specimen Stability for Testing:
Centrifuged SST Tubes and Microtainers® with Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 8 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable
Red-top Tubes and Microtainers® without Separator Gels
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable
Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months
Specimen Storage in Department Prior to Disposal:
Refrigerated (2-8°C or 36-46°F): 7 days
Laboratory
Royal Oak Special Testing Laboratory
Performed
Tuesday, Wednesday, Friday.
Results available in 2 business days.
Reference Range
Negative: < 15 U/mL
Equivocal: NA
Positive: ≥ 15 U/mL
Test Methodology
Multiplex Flow Assay.
Interpretation
Tissue transglutaminase antibodies appear to be highly specific for celiac disease and are useful to screen high-risk populations (e.g. first degree relatives of celiac patients, insulin dependent diabetics, etc.) for celiac disease. However, histologic confirmation is required for diagnosis. Patients should not begin a gluten-free diet until after intestinal biopsy has been performed and the diagnosis is established. Serial tissue transglutaminase antibody testing may at times be useful to monitor dietary compliance.
Note: The endomysial antigen has been identified as the protein cross-linking enzyme known as tissue transglutaminase. Detection of tissue transglutaminase antibodies is an aid in the diagnosis of certain gluten-sensitive enteropathies, such as celiac disease and dermatitis herpetiformis. Human tTg IgA antigen is used in this assay.
Clinical Utility
Tissue transglutaminase is an enzyme that is normally located within endomysial cells. IgA autoantibodies to tissue transglutaminase have been shown to be highly correlated with active celiac disease.
Note: Patients with IgA deficiency may have falsely negative test results. If there is a high degree of suspicion for celiac disease, tissue transglutaminase antibodies (IgG) and an IgA level should be requested.
CPT Codes
83516
LOINC: 46128-5
Contacts
Special Chemistry Laboratory – RO
248-551-8044
Name: Special Chemistry Laboratory – RO
Location:
Phone: 248-551-8044
Last Updated
7/21/2024
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