Do I need to be eating gluten before this test?

Yes, it's essential to continue eating gluten-containing foods before testing. Gluten avoidance can cause antibody levels to decrease within weeks, potentially leading to false-negative results. Most experts recommend consuming gluten daily for at least 6-8 weeks prior to testing for optimal accuracy.

What happens if I have IgA deficiency?

If your total IgA is low or deficient, the tTG-IgA test may not be reliable. In such cases, additional testing with IgG-based antibodies (like tTG-IgG or deamidated gliadin IgG) may be recommended to accurately screen for celiac disease. IgA deficiency affects 2-3% of people with celiac disease.

Can this test definitively diagnose celiac disease?

While highly accurate, blood tests alone typically cannot provide a definitive celiac disease diagnosis. Positive antibody results usually require confirmation through intestinal biopsy or, in some cases, genetic testing. However, very high tTG-IgA levels (10+ times normal) combined with symptoms may be sufficient for diagnosis in some situations.

How long after starting a gluten-free diet do antibody levels normalize?

Antibody levels typically begin to decline within weeks to months of starting a strict gluten-free diet. Complete normalization may take 6 months to 2 years, depending on individual factors and adherence to the diet. This is why testing must be done while still consuming gluten for accurate results.

Are there other conditions that can cause positive results?

While tTG-IgA is highly specific for celiac disease, occasionally other autoimmune conditions like type 1 diabetes, autoimmune thyroid disease, or liver disease may cause mild elevations. However, significantly elevated levels are typically associated with celiac disease, especially when accompanied by appropriate symptoms.

Is this test accurate in children?

Yes, the tTG-IgA test is generally accurate in children over age 2-3 years, provided they have been consuming gluten-containing foods. For very young children (under 2 years), additional tests like deamidated gliadin peptide antibodies may be needed, as the immune response to gluten may not be fully developed.

Autoimmune & Inflammation

Celiac Disease Panel (tTG-IgA + Total IgA)

A comprehensive screening test that measures tissue transglutaminase IgA antibodies and total IgA levels to help identify celiac disease and rule out IgA deficiency.

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Blood

What this test measures

This panel measures two important components for celiac disease screening: tissue transglutaminase IgA antibodies (tTG-IgA) and total immunoglobulin A (IgA) levels. The tTG-IgA test will be positive in about 93% of patients with celiac disease who are on a gluten-containing diet, with approximately 95% sensitivity and 99% specificity. Tissue transglutaminase is an enzyme found in the small intestine that becomes a target of the immune system in individuals with celiac disease when they consume gluten-containing foods.

Total IgA measurement is essential because this test is used to check for IgA deficiency, a condition associated with celiac disease that can cause a false negative tTG-IgA or EMA result. The incidence of IgA deficiency in patients with celiac disease is somewhere between 2 and 3%, representing an increase of 10- to 15-fold over the general population. When individuals have IgA deficiency, the standard tTG-IgA test may not accurately detect celiac disease, making the total IgA measurement critical for proper interpretation of results.

What's included

Tissue Transglutaminase IgA Antibodies (tTG-IgA)

Total Immunoglobulin A (IgA)

Who should consider this test

You might consider this test if you are experiencing any of the following:

Individuals experiencing unexplained digestive symptoms such as chronic diarrhea, abdominal pain, bloating, or malabsorption
Those with a family history of celiac disease, as first-degree relatives have up to a 10-fold increased risk compared to the general population
People with autoimmune conditions including type 1 diabetes, autoimmune thyroid disease, or autoimmune liver disease, which are associated with higher celiac disease rates
Individuals with unexplained iron deficiency anemia, unexplained weight loss, or failure to thrive (especially in children)
Those with dermatitis herpetiformis or other skin conditions that may be related to gluten sensitivity
Adults or children with Down syndrome, Turner syndrome, or Williams syndrome, who have increased risk for celiac disease

What to expect

Preparation

Individuals must continue eating gluten-containing foods before testing, as gluten avoidance can cause antibody levels to decrease and lead to false-negative results. No fasting is required for this test.

Sample Type

A simple blood draw from a vein in the arm, typically taking just a few minutes to complete.

Collection

The blood sample is collected by a trained phlebotomist at any participating laboratory location. No special handling or timing requirements are needed.

Turnaround

Results are typically available within 2-3 business days after the laboratory receives the sample.

Understanding your results

For tissue transglutaminase IgA, negative results are typically less than 15 U/mL, while positive results are 15 U/mL or greater. The total IgA level helps ensure the tTG-IgA results can be properly interpreted. If total IgA is decreased, reflex testing for tissue transglutaminase IgG antibodies may be performed. Results should always be interpreted in the context of clinical symptoms and dietary gluten consumption, as testing accuracy depends on ongoing gluten intake.

Population	Reference Range	Notes
Adults	Total IgA: 60-400 mg/dL; tTG-IgA: <15 U/mL (negative)	Normal total IgA levels indicate the body produces sufficient IgA for accurate tTG-IgA testing
Children	Total IgA varies by age; tTG-IgA: <15 U/mL (negative)	Total IgA levels progressively increase with age from newborn to adult levels

Reference ranges shown are general guidelines. Your lab report will include the specific reference range used by the laboratory that processed your sample, which is the authoritative range for interpreting your results.

What does a “Low” result mean?

Low or undetectable total IgA levels indicate IgA deficiency, which affects the reliability of IgA-based celiac tests. The incidence of IgA deficiency in patients with celiac disease is somewhere between 2 and 3%. When IgA deficiency is present, alternative testing using IgG-based antibodies (such as tTG-IgG or deamidated gliadin IgG) may be necessary for accurate celiac disease screening. Low tTG-IgA levels generally suggest the absence of celiac disease, provided total IgA is adequate for testing.

What does a “High” result mean?

Elevated tTG-IgA antibodies typically suggest celiac disease, particularly when levels are significantly above normal ranges. A tTG IgA titer of 10 or more times the upper limit of normal had a positive predictive value of 95% in an adult population. However, other conditions may occasionally cause elevated tTG-IgA levels, including autoimmune liver disease, heart failure, or certain infections. High total IgA levels may be associated with chronic infections, liver disease, or certain autoimmune conditions, though this is less specific than tTG-IgA elevation.

Privacy & confidentiality

All test orders are authorized and results reviewed by an independent, board-certified physician who is not the patient's personal doctor. Your celiac disease testing results are handled with complete confidentiality and privacy protection. These results are not reported to your personal doctor unless you specifically choose to share them, and they are not part of your medical records unless you provide them to your healthcare provider. The test results will not appear on insurance statements or explanations of benefits, ensuring your privacy regarding this health information. Your employer, insurance company, and other third parties cannot access these results without your explicit consent. This confidential testing approach allows individuals to explore potential celiac disease without concerns about insurance implications or medical record documentation, providing peace of mind while seeking answers about digestive health concerns. With no doctor visit required, individuals can take control of their health screening privately and conveniently.

Frequently asked questions

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CPT Code: 86364, 82784

This test may not be available in: NY, NJ, RI

This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.

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