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HelpOrder Code TSTGP Tissue Transglutaminase Antibodies, IgA and IgG Profile, Serum
Reporting Name
Tissue Transglutaminase Ab, IgA/IgGUseful For
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 disease, positivity for HLA DQ2 and/or DQ8)
Screening for dermatitis herpetiformis, in conjunction with endomysial antibody test
Monitoring response to gluten-free diet in patients with dermatitis herpetiformis and celiac disease
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TTGA | Tissue Transglutaminase Ab, IgA, S | Yes | Yes |
| TTGG | Tissue Transglutaminase Ab, IgG, S | Yes | Yes |
Testing Algorithm
The following algorithms are available:
-Celiac Disease Comprehensive Cascade Test Algorithm
-Celiac Disease Diagnostic Testing Algorithm
-Celiac Disease Gluten-Free Cascade Test Algorithm
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering 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
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
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 Minimum Volume
0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 21 days |
| Frozen | 21 days |
Special Instructions
Reference Values
tTG ANTIBODY, IgA
<4.0 U/mL (negative)
4.0-10.0 U/mL (weak positive)
>10.0 U/mL (positive)
Reference values apply to all ages.
tTG ANTIBODY, IgG
<6.0 U/mL (negative)
6.0-9.0 U/mL (weak positive)
>9.0 U/mL (positive)
Reference values apply to all ages.
Day(s) Performed
Monday through Saturday
CPT Code Information
86364 x 2
Method Description
Microwells are precoated with recombinant human tissue transglutaminase (tTG) antigen expressed in Baculovirus cells using a complementary DNA coding for the long-spliced isoform of human tTG.
Calibrators, controls, and diluted patient samples are added to the wells, and autoantibodies recognizing the tTG antigen bind during the first incubation. After washing the wells to remove all unbound proteins, purified peroxidase-labeled rabbit antihuman IgG (gamma chain specific for detection of tTG IgG) or antihuman IgA (alpha chain specific for detection of tTG IgA) conjugate is added. The conjugate binds to the captured human autoantibody, and the excess unbound conjugate is removed by a further wash step.
Bound conjugate is visualized with 3,3',5,5'-tetramethylbenzidine substrate, which gives a blue reaction product, the intensity of which is proportional to the concentration of the autoantibody in the sample. Phosphoric acid is added to each well to stop the reaction. This produces a yellow end point color, which is read at 450 nm.(Package inserts: QUANTA Lite R h-tTG IgA and IgG. Inova Diagnostics, Inc; Rev. 8, 01/2020)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
Method Name
Enzyme-Linked Immunosorbent Assay (ELISA)
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.