Gliadin (Deamidated Peptide) Antibody (IgG, IgA)

Cleveland HeartLab G, Test

NEW YORK DOH APPROVED: YES
CPT Code: 83516 (x2)
Order Code: C1496
ABN Requirement: No
Synonyms: Antigliadin Ab (IgA, IgG); Deamidated Gliadin (IgA, IgG); Anti-Gliadin Ab (IgA, IgG); Gliadin (IgA, IgG); DGP (IgA, IgG)
Specimen: Serum
Volume:  2.0 mL
Minimum Volume:  1.0 mL
Container: Gel-barrier tube (SST, Tiger Top)

Collection:

Serum:

  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. Let tube stand in a vertical position to allow blood to clot 30 minutes.
  4. Centrifuge at 1300 rcf for 10 minutes at room temperature.

Transport: Store serum at 2-8°C after collection and ship the same day per packaging instructions provided with the Cleveland HeartLab, Inc. shipping box.

Stability:

Ambient (15-25°C): 4 days
Refrigerated (2-8°C):
7 days
Frozen (-20°C):
30 days
Deep Frozen (-70°C):
30 days

Causes for Rejection: Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits; grossly hemolyzed or lipemic samples

Methodology: Immunoassay (IA)

Turn Around Time: 5 days

Reference Range:

Component Age Ab Not Detected Ab Detected
Gliadin Ab (IgG) All Ages <20 Units ≥20 Units
Gliadin Ab (IgA) All Ages <20 Units ≥20 Units

 


Intended Use: Evaluation of possible celiac disease.

Clinical Significance: Detection of antibodies to gliadin, one of the major protein components of gluten, is a sensitive assay useful in diagnosis celiac disease However, gliadin antibodies may be found in individuals without celiac disease; thus gliadin antibody assays are less specific than assays measuring antibodies to endomysium and transglutaminase. Recent work has revealed that gliadin-reactive antibodies from celiac patients bind to a very limited number of specific epitopes on the gliadin molecule. Further, deamidation of gliadin results in enhanced binding of gliadin antibodies. Based on this information, assays using deamidated gliadin peptides bearing the celiac-specific epitopes have much higher diagnostic accuracy for celiac disease when compared to standard gliadin antibody assays.

Limitations: Tissue transglutaminase (tTG; IgA) antibody is an excellent first-line marker, with high sensitivity and specificity in untreated individuals. The endomysial antibody (EMA; IgA) assay has high specificity for celiac disease and is used to confirm positive IgA anti-tTG results. Although this panel tests for EMA only when anti-tTG (IgA) results are positive, EMA testing can be ordered separately if the IgA anti-tTG result is negative but clinical suspicion remains high. Some patients with limited villous atrophy have been reported to lack EMA and tTG antibodies; testing for IgA antigliadin antibody (AGA) may help detect celiac disease in such patients. Total serum IgA is measured to identify selective IgA deficiency, present in about 2-10% of celiac disease patients. Such patients would have negative results on IgA anti-tTG and EMA assays but may have positive IgG anti-tTG results.