Expected Turnaround Time
2 - 3 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Collection
Specimen should be free of bacterial contamination, hemolysis, and lipemia.
Storage Instructions
Room temperature
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination
Test Details
Use
Detection of antibodies to aid in the diagnosis of gluten-sensitive enteropathy (GSE), such as celiac disease and dermatitis herpetiformis
Limitations
A negative tTG IgA result in an untreated patient does not rule out gluten-sensitive enteropathy. This result can often be explained by selective IgA deficiency, a relatively frequent finding in celiac disease. Results of this assay should be used in conjunction with clinical findings and other serological tests.
Methodology
Enzyme immunoassay (EIA)
Reference Interval
• Negative: 0−3 units/mL
• Weak positive: 4−10 units/mL
• Positive: >10 units/mL
Additional Information
Studies have demonstrated that IgA endomysial antibody tests have >99% specificity for gluten-sensitive enteropathy.1 Recently, the endomysial antigen has been identified as the protein cross-linking enzyme known as tissue transglutaminase (tTG).2
Footnotes
1. Volta U, Molinaro N, De Franchis R, et al. Correlation between IgA antiendomysial antibodies and subtotal villous atrophy in dermatitis herpetiformis. J Clin Gastroenterol. 1992 Jun; 14(4):298-301. 1607605
2. Dieterich W, Ehnis T, Bauer M, et al. Identification of tissue transglutaminase as the autoantigen of celiac disease. Nat Med. 1997 Jul; 3(7):797-801. 9212111
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 164640 | t-Transglutaminase (tTG) IgA | 31017-7 | 164643 | t-Transglutaminase (tTG) IgA | U/mL | 31017-7 |
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