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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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
This panel screens for celiac disease using two complementary measurements: tissue transglutaminase IgA antibodies (tTG-IgA) and total immunoglobulin A (IgA). 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. The tTG-IgA test detects antibodies against this enzyme with approximately 95% sensitivity and 99% specificity, making it the most reliable single blood marker for celiac screening.
The total IgA measurement serves a critical quality-control function. IgA deficiency occurs at a rate roughly 10 to 15 times higher among people with celiac disease than in the general population, affecting an estimated 2% to 3% of celiac patients. When IgA is deficient, the tTG-IgA test can produce a falsely negative result because the body is not manufacturing enough of the antibody class being measured. Identifying IgA deficiency allows the laboratory to reflexively test for tTG-IgG instead, ensuring the screen remains accurate.
What's included
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 tTG-IgA, values below 15 U/mL are generally considered negative, while values at or above 15 U/mL are positive and suggest an immune response consistent with celiac disease. The total IgA result provides context for interpreting the tTG-IgA: if total IgA is low, the laboratory may perform reflex testing using IgG-based antibodies to avoid a false negative. Results must be interpreted in the context of current dietary gluten consumption, since individuals who have already eliminated gluten may show falsely normal antibody levels. A positive result typically prompts referral for intestinal biopsy, which remains the definitive diagnostic step.
| 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 <u>not reported to your personal doctor</u> unless you specifically choose to share them, and they are <u>not part of your medical records</u> unless you provide them to your healthcare provider. The test results will <u>not appear on insurance statements</u> 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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Last reviewed: April 2026
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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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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