From the Guidelines
Low Immunoglobulin A (IgA) levels in a celiac disease panel are significant because they may indicate IgA deficiency, which can lead to false-negative results in serological tests for celiac disease.
Key Points
- IgA deficiency is an important consideration in patients with suspected celiac disease, as it can affect the accuracy of serological tests 1.
- Patients with IgA deficiency may require IgG-based testing, such as IgG tissue transglutaminase (tTG) and IgG deamidated gliadin peptide (DGP), to diagnose celiac disease 1.
- A low IgA level in a celiac disease panel should prompt further evaluation, including measurement of total IgA levels and consideration of IgG-based testing 1.
- The prevalence of IgA deficiency in celiac disease is higher than in the general population, making it an important consideration in patients with suspected celiac disease 1.
Clinical Implications
- Clinicians should be aware of the potential for IgA deficiency in patients with suspected celiac disease and take steps to evaluate for it, including measuring total IgA levels and considering IgG-based testing 1.
- IgA deficiency can lead to false-negative results in serological tests for celiac disease, highlighting the importance of considering this condition in patients with suspected celiac disease 1.
- The use of IgG-based testing in patients with IgA deficiency can help improve the accuracy of celiac disease diagnosis 1.
From the Research
Significance of Low Immunoglobulin A (IgA) in Celiac Disease Panel
- Low IgA levels can lead to false-negative results in serologic tests for celiac disease, such as endomysial IgA (EMA) testing 2
- IgA deficiency is more common in patients with celiac disease, occurring in 2-3% of celiac disease patients 3
- Patients with selective IgA deficiency have a 10- to 20-fold increased risk of celiac disease 4
- IgG-specific antibody tests, such as IgG gliadin and tissue transglutaminase antibodies, can be useful in diagnosing celiac disease in IgA-deficient patients 5
Diagnostic Challenges
- IgA-based serology may not be reliable in patients with selective IgA deficiency, but positive results can still be observed 4
- IgG antibody tests can help identify IgA-deficient patients with celiac disease, but may not be sufficient on their own 5
- Villous atrophy and gastrointestinal symptoms can still be present in IgA-deficient patients with celiac disease, even if serologic tests are negative 3
Clinical Implications
- IgA deficiency can be associated with autoimmune diseases, including celiac disease 6
- Patients with IgA deficiency and celiac disease may have a lower incidence of autoimmune diseases compared to those without IgA deficiency 3
- Including IgA dosing in the diagnosis of celiac disease can help identify patients with selective IgA deficiency and ensure accurate diagnosis 3