Does the patient have celiac disease based on the provided antibody test results?

Celiac Disease Serologic Evaluation

Based on these test results, the patient does NOT have celiac disease. All celiac-specific antibodies are negative, making active celiac disease highly unlikely.

Interpretation of Results

Negative Serologic Markers

• Tissue transglutaminase IgA (tTG-IgA): 1.0 ELU/mL - This is well below the diagnostic threshold of 7.0 ELU/mL and represents the preferred first-line screening test with 90.7% sensitivity and 87.4% specificity in adults 1
• Endomysial antibody (EMA): <1:10 - Negative result with excellent specificity of 99.6% 1
• Deamidated gliadin peptide IgA: 6.1 ELU/mL - Below the 7.0 ELU/mL threshold, though this is the closest value to the equivocal range (7.0-10.0) 1
• Deamidated gliadin peptide IgG: <1.4 ELU/mL - Negative, well below threshold 1
• Tissue transglutaminase IgG: <1.7 ELU/mL - Negative, though IgG-based tests are primarily useful only in IgA-deficient patients 2

Clinical Significance

• The combination of negative tTG-IgA and negative EMA effectively excludes celiac disease in patients with normal IgA levels 2
• The gliadin IgA value of 6.1 ELU/mL, while the highest result, remains in the negative range and does not suggest celiac disease 1
• All antibody tests must be performed while the patient is consuming adequate gluten (at least 10g daily for 6-8 weeks) to avoid false-negative results 3, 4

Important Considerations

Verify Testing Conditions

• Confirm the patient was on a gluten-containing diet at the time of testing - If the patient had already reduced or eliminated gluten intake, these results could be falsely negative and testing should be repeated after gluten reintroduction for 1-3 months 3, 4

IgA Deficiency Assessment

• While not shown in these results, total IgA levels should be measured to rule out selective IgA deficiency, which occurs in 1-3% of celiac disease patients and would cause falsely negative IgA-based antibody tests 2, 3, 4
• If IgA deficiency is present, IgG-based tests (particularly IgG deamidated gliadin peptide) should be used instead, with superior diagnostic accuracy of 93.6% sensitivity and 99.4% specificity 2

Alternative Diagnoses

• With negative celiac serology, consider other causes of gastrointestinal symptoms if present, including irritable bowel syndrome, inflammatory bowel disease, bile acid diarrhea, or non-celiac gluten sensitivity 1
• Non-celiac gluten sensitivity requires negative celiac antibodies, normal duodenal histology, and symptom improvement with gluten-free diet 5

When to Reconsider Testing

High-Risk Populations

• If the patient belongs to a high-risk group (first-degree relatives with celiac disease, type 1 diabetes, autoimmune thyroid disease, unexplained iron deficiency anemia), and clinical suspicion remains high despite negative serology, consider upper endoscopy with duodenal biopsy 2, 4
• In these populations, biopsy may occasionally reveal celiac disease even with negative serology, though this is uncommon 2

Repeat Testing Scenarios

• If symptoms persist and the patient was not consuming adequate gluten during initial testing, repeat serologic testing after 6-8 weeks of gluten consumption (at least 10g daily) 3, 4
• If clinical suspicion remains very high, HLA-DQ2/DQ8 testing has high negative predictive value (>99%) - absence of these alleles essentially rules out celiac disease 3, 4

Common Pitfalls to Avoid

• Do not initiate a gluten-free diet based on these negative results - There is no serologic evidence of celiac disease 3
• Do not proceed to duodenal biopsy - With negative serology in a patient without high-risk features, biopsy is not indicated 2, 6
• Ensure adequate gluten intake was present during testing - This is the most common cause of false-negative results 3, 4