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Tissue Transglutaminase Antibody, IgG

Tissue Transglutaminase (tTG) Antibody, IgG

Test Codes

EPIC: LAB1231800, Beaker: XTTGG

Department

Immunology

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Also acceptable: One Red-top tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below). (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (Minimum: 0.5 mL)

Rejection Criteria

• Plasma specimens.
• Severely hemolyzed or lipemic specimens. 

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below). (Minimum: 0.5 mL)

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (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 Chemistry 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 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.

CPT Codes

83516
LOINC: 46128-5

Contacts

Last Updated

2/13/2025