Interpretation of Celiac Screen Results
A tissue transglutaminase IgA antibody level less than 1 U/mL with a normal total IgA of 321 mg/dL effectively rules out celiac disease; the elevated total IgA does not indicate celiac disease but may reflect other inflammatory or infectious conditions unrelated to gluten. 1, 2
Understanding Your Test Results
Your celiac screen shows two key findings that work together:
The negative tTG IgA (<1 U/mL) excludes celiac disease with high confidence. IgA tissue transglutaminase antibody testing demonstrates 90.7% sensitivity in adults at the standard 15 U/mL threshold, making it highly reliable for ruling out disease when negative. 3
The normal total IgA level (321 mg/dL) confirms the validity of your negative tTG IgA result. This is critical because IgA deficiency occurs in 1-3% of celiac patients and causes falsely negative IgA-based antibody tests; your normal IgA proves this is not the case. 1, 4
An undetectable tTG IgA (<1.2 U/mL) provides even stronger evidence against celiac disease compared to values in the low-positive range (1.2-3.9 U/mL), as demonstrated in treated celiac patients where undetectable levels correlate with complete mucosal healing. 5
What the Elevated Total IgA Actually Means
Your elevated total IgA of 321 mg/dL does NOT indicate celiac disease or "high inflammation" related to gluten:
Elevated total IgA strengthens confidence in your negative celiac screen rather than suggesting hidden disease, because it confirms your immune system produces adequate IgA antibodies. 1, 2
Multiple non-celiac conditions commonly elevate total IgA levels, including chronic infections, inflammatory bowel disease (Crohn's disease or ulcerative colitis), chronic liver disease (cirrhosis or chronic hepatitis), and autoimmune conditions. 1
IgA-related disorders should be considered based on your clinical symptoms, such as IgA nephropathy (kidney disease with blood or protein in urine), IgA vasculitis (skin rash with joint or abdominal pain), or rarely IgA monoclonal gammopathy. 1
Critical Verification Before Accepting These Results
Before concluding celiac disease is excluded, verify you were consuming adequate gluten when tested:
You must have eaten at least 10 grams of gluten daily (approximately 3-4 slices of wheat bread) for 6-8 weeks prior to testing to ensure reliable results. 1, 2
If you had already reduced or eliminated gluten before testing, these results are unreliable and testing must be repeated after gluten reintroduction for 1-3 months. 1, 2
What to Do Next
No further celiac-specific testing is needed if you were consuming adequate gluten when tested. 1, 2
Investigate the elevated total IgA and your symptoms through:
- Comprehensive metabolic panel and liver function tests to evaluate for chronic liver disease 1
- Urinalysis with microscopy to screen for IgA nephropathy if you have kidney-related symptoms 1
- Fecal calprotectin or lactoferrin if you have chronic diarrhea, to evaluate for inflammatory bowel disease 2
- Serum protein electrophoresis if clinically indicated based on other findings 1
Common Pitfalls to Avoid
Never start a gluten-free diet based on symptoms alone without confirmed celiac disease, as this leads to nutritional deficiencies and unnecessary dietary restrictions. 1, 2
Do not confuse elevated total IgA with celiac disease risk—the two are unrelated, and your elevated IgA actually validates your negative celiac antibody test. 1, 2
False-negative celiac serology is extremely rare (approximately 19 per 10,000 adults tested) when total IgA is normal and adequate gluten was consumed before testing. 1