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Laboratory:

Clinical Immunology

Test Name:

TISSUE TRANSGLUTAMINASE IgA (TTG-A) - (S)

Test Code: TTGA

Clinical Information:

Alternate Name(s):
Celiac Disease

Coeliac Disease

Tissue Transglutaminase (tTG)

Tissue Transglutaminase Ab IgA

Transglutaminase(tTG)

Test Indications: Presence of the tissue transglutaminase (tTG) IgA antibody is associated with gluten-sensitive enteropathies such as celiac disease and dermatitis herpetiformis (Durhing’s disease).

Collection Devices:

Preferred Device:

1 - Serum Separator (SST) Tube(s) - Full Tube Collection

Specimen Required:

Serum: 1.0 mL

Referral:

Serum: 1.0 mL

Shipping & Storage: Separate serum and ship refrigerated, or frozen if greater than 7 days from time of collection.

Testing Laboratory (MB): St. Boniface Hospital Immunology Laboratory

Requisition:

_SH Immunology Autoimmune Laboratory Requisition (R250-10-85)

Reference Values:

Reference Intervals: 0.0 – 9.9 AU/ml
A negative result does not necessarily exclude autoimmune disease. Positive results should not be interpreted in isolation and must be correlated with relevant clinical findings.

A decrease in tTG IgA antibody concentration after initiation of a gluten-free diet may indicate a response to therapy.

Method of Analysis: The IDS t-TG IgA assay is based on chemiluminescence technology. Patient serum is incubated with magnetic particles coated with the specific antigen. Following the washing step after the first incubation, an anti-human IgA antibody labelled with acridinium is added, followed by a subsequent incubation step. The magnetic particles are captured using a magnet and a wash step performed to remove any unbound analyte. Trigger reagents are added; the resulting light emitted by the acridinium label is directly proportional to the concentration of anti-t-TG IgA in the sample. For samples that do not contain anti-t-TG IgA, the assay also provides an indication of the concentration of the total IgA present in the sample.

Samples determined to be IgA deficient (≤0.07g/L), and all children ≤3years of age, will automatically reflex to Deamidated Gliadin IgG.

Pediatric positive samples ≥10.0 AU/ml will automatically reflex to Endomysial antibody testing by immunofluorescence (all instances).

Adult positive samples in the range 10.0 – 100.0 AU/ml will automatically reflex to Endomysial antibody testing by immunofluorescence (first instance only).

Reference: IDS t-TG IgA Instructions for Use, IS-AI1303 V08, 17-11-2025

Availability:

Weekdays

TAT: 3-5 Days