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Mar 23, 2015

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UWHC,UWMF,

Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Immunology

Tissue Transglutaminase Ab, IgA

Tissue Transglutaminase Ab, IgA (XTTGA) Immunology Lab Test

Name: Tissue Transglutaminase Ab, IgA

Test Name: Tissue Transglutaminase Ab, IgA

Health Link Test Code: XTTGA

LIS Test Code: TTGIGA

CPT Code(s): 83516

Methodology: ELISA

Clinical Information:

Tissue Transglutaminase antibody assays are now considered the most sensitive and specific serologic tests for celiac disease. Although classically considered a gastrointestinal disorder, celiac disease can actually present with a variety of intestinal and extra-intestinal symptoms. It is an immune-mediated disorder triggered by exposure to specific dietary proteins (glutens) in wheat, barley, and rye. Affected individuals will show inflammation and atrophy of the small intestine on biopsy; this is the gold standard for diagnosis. Treatment is a gluten-free diet for life.

Days Performed: Mon-Fri, dayshift - day varies.

In-Lab Turnaround Time: 2 - 5 days.

Stat In-Lab Turnaround Time: Not available stat.

Specimen: Blood

Collection Container: Red top

Also Acceptable: Red cap with yellow ring (SST)

Collection Volume: 3 mL

Pediatric Collection Volume: 1 mL

Stability Ambient:

2 days

Stability Refridgerated:

14 days at 2-8°C

Stability Frozen:

3 months at -20°C or lower

Sample Analyzed: Serum

Testing Volume: 1 mL

Pediatric Testing Volume: 0.3 mL

Specimen Processing:

Centrifuge. Transfer cell-free serum to clear plastic vial. Refrigerate.

Specimen Transport:

Transport specimen to UWHC Hospital Laboratory. Transport with coolant pack if coming from clinic locations.

Unacceptable Criteria:

Grossly hemolyzed or grossly lipemic samples Plasma and other body fluids

Interpretation:

6 years and up:

Negative <20 units
Borderline 20-30 units
Moderate to Strong Positive >30 units

Assay peformance not established for pediatric population under age 6.

Interpretation Type: Reference Interval

Test Limitations:

This test has high sensitivity and specificity for biopsy proven celiac disease. A small portion of the population is IgA deficient and will have a negative IgA TTg antibody test. If the patient has a high clinical suspicion of celiac disease and the IgA TTg antibody test is negative, quantitative serum IgA levels should be measured. If the patient is IgA deficient, IgG TTg antibody testing is recommended.  The Immunology Laboratory will review IgG TTg antibody requests prior to sending them out.

 

Individuals on a gluten-free diet may have a negative IgA TTg result.