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Test Code Billings Clinic: 9326 Mayo: TTGG Tissue Transglutaminase Antibody, IgG, Serum

Reporting Name

Tissue Transglutaminase Ab, IgG, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

For individuals with IgA deficiency:

 

Evaluating patients suspected of having celiac disease, including patients with compatible clinical symptoms, patients with atypical symptoms, and individuals at increased risk (family history, previous diagnosis with associated disorder, positivity for HLA DQ2 and/or DQ8

 

Screening test for dermatitis herpetiformis, in conjunction with an endomysial antibody test

 

Monitoring response to gluten-free diet in patients with dermatitis herpetiformis and celiac disease

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)


Ordering Guidance


Cascade testing is recommended for celiac disease. Cascade testing ensures that testing proceeds in an algorithmic fashion. The following cascades are available; select the appropriate one for your specific patient situation.

-CDCOM / Celiac Disease Comprehensive Cascade, Serum and Whole Blood: complete testing including HLA DQ

-CDSP / Celiac Disease Serology Cascade, Serum: complete serology testing excluding HLA DQ

-CDGF / Celiac Disease Gluten-Free Cascade, Serum and Whole Blood: for patients already adhering to a gluten-free diet

To order individual tests, see Celiac Disease Diagnostic Testing Algorithm.



Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Type

Serum

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK

Reference Values

<6.0 U/mL (negative)

6.0-9.0 U/mL (weak positive)

>9.0 U/mL (positive)

Reference values apply to all ages.

Interpretation

Positive results for tissue transglutaminase (tTG) IgG antibodies are consistent with a diagnosis for celiac disease, particularly in individuals who are IgA deficient. For individuals with moderately to strongly positive results, a diagnosis of celiac disease is possible and a small intestinal biopsy should be considered to confirm the diagnosis.

 

Negative results for tTG IgG antibodies indicate a decreased likelihood of celiac disease.

 

A decrease in the concentration of tTG IgG may begin after initiation of a gluten-free diet and could indicate a response to therapy.

Day(s) Performed

Monday through Saturday

Report Available

Same day/1 to 4 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86364

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TTGG Tissue Transglutaminase Ab, IgG, S 56537-4

 

Result ID Test Result Name Result LOINC Value
TTGG Tissue Transglutaminase Ab, IgG, S 56537-4

Forms

If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.