Name: Tissue Transglutaminase Ab, IgA
Test Name: Tissue Transglutaminase Ab, IgA
Health Link Test Code: XTTGA
LIS Test Code: TTGIGA
CPT Code(s): 83516
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.
Collection Container: Red top
Also Acceptable: Red cap with yellow ring (SST)
Collection Volume: 3 mL
Pediatric Collection Volume: 1 mL
14 days at 2-8°C
3 months at -20°C or lower
Sample Analyzed: Serum
Testing Volume: 1 mL
Pediatric Testing Volume: 0.3 mL
Centrifuge. Transfer cell-free serum to clear plastic vial. Refrigerate.
Transport specimen to UWHC Hospital Laboratory. Transport with coolant pack if coming from clinic locations.
Grossly hemolyzed or grossly lipemic samples Plasma and other body fluids
6 years and up:
|Moderate to Strong Positive||>30 units|
Assay peformance not established for pediatric population under age 6.
Interpretation Type: Reference Interval
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.