Gliadin (Deamidated) Antibody, IgA, Serum

CPT CODE:

USEFUL FOR:

Evaluating patients suspected of having celiac disease, includingpatients with symptoms compatible with celiac disease, patients withatypical symptoms, and individuals at increased risk of celiac disease
Evaluating the response to treatment with a gluten-free diet

SPECIMEN REQUIRED:

Draw blood in a plain, red-top tube(s) or a serum gel tube(s). Spin down and send 0.5 mL of serum refrigerated.

TRANSPORT TEMPERATURE:

Refrig\Frozen OK\Ambient < 72 hours OK

CLINICAL INFORMATION:

Ingestion of gliadin peptides contained in wheat, rye, and barleyinduces immune-mediated inflammation of the small intestine in geneticallysusceptible individuals with celiac disease (gluten sensitive enteropathy,celiac sprue).(1-4) It is estimated that this disease occurs with a prevalenceof 0.5% to 1% in the United States and Europe. Non-Caucasian ethnicgroups may be at lower risk. Greater than 97% of affected individuals inthe United States have the DQ2 and/or DQ8 HLA markers compared toapproximately 40% of the general population. Celiac disease is morecommon in first- and second-degree relatives of patients with the disease,individuals with Down syndrome, Turner syndrome, Williams syndrome,selective IgA deficiency, and autoimmune disorders.
Inflammation in typical celiac disease occurs primarily in the mucosa ofthe small intestine resulting in villous atrophy with malabsorption oftenaccompanied by diarrhea and abdominal pain. The disease maypresent at any age. Celiac disease is a multisystem disorder, and theclinical manifestations are extremely variable and may involve multipleorgan systems. Common clinical manifestations includegastrointestinal signs and symptoms (abdominal pain, anorexia, diarrhea,constipation), failure to grow with delayed puberty and short stature, irondeficiency, recurrent fetal loss, osteoporosis, chronic fatigue, recurrentaphthous stomatitis (canker sores), dental enamel hypoplasia, anddermatitis herpetiformis, as well as elevated transaminases. Celiacdisease is associated with autoimmune endocrinologic disorders,including thyroiditis and type I diabetes mellitus. Patients with celiacdisease may also present with neuropsychiatric manifestations includingataxia and peripheral neuropathy. There is an increased risk of non-Hodgkin lymphoma for patients with celiac disease. Adherence to alifelong gluten-free diet ameliorates the signs and symptoms of diseasementioned above, and may reduce the risk of lymphoma.
No single laboratory test is completely reliable for establishing thediagnosis of celiac disease. Testing for antibodies associatedwith celiac disease offers a rapid, sensitive and specific approach topatients suspected of having celiac disease. All serologic tests orderedfor the diagnosis of celiac disease should be performed while the patientis on a gluten-containing diet. The most sensitive and specific test forceliac disease is #83671 "Tissue Transglutaminase (tTG) Antibodies IgAand IgG Profile, Serum." The sensi

CLINICAL INTERPRETATION:

Positive test results for deamidated gliadin antibodies, IgA or IgG, areconsistent with the diagnosis of celiac disease or dermatitis herpetiformis,a blistering skin disorder associated with gluten sensitivity.
Negative results indicate a decreased likelihood of celiac disease.
Decreased levels of deamidated gliadin antibodies, IgA or IgG, followingtreatment with a gluten-free diet are consistent with adherence to the diet.Persistence of high levels of antibodies following dietary treatment suggestpoor adherence to the diet.
See "Celiac Disease Diagnostic Testing Algorithm" in Special Instructions for the recommended approach to a patient suspected of celiac disease.        

REFERENCE VALUES:

Negative: <20.0 U

Weak positive: 20.0-30.0 U

Positive: >30.0 U