IgA, or the immunoglobulin A type of antibody, helps your body fight off common threats such as bacteria, viruses and toxins. Research shows that people with celiac disease are about 10 to 15 times more likely to have IgA deficiency than people without the condition.
If your total serum IgA test shows that you're IgA-deficient, that doesn't necessarily indicate you have celiac disease.
However, it does indicate that several of the other celiac blood tests, including the AGA-IgA, tTG-IgA and the EMA-IgA, won't produce accurate results because all rely on normal amounts of circulating IgA.
If you're IgA-deficient, your physician will rely more on the results of your AGA-IgG blood test to determine whether you should undergo an endoscopy to diagnose celiac disease.
Celiac Disease Frequently Asked Questions. University of Maryland Center for Celiac Research. Accessed Feb. 14, 2011.
Serologic and Genetic Testing. Celiac Disease Center at Columbia University. Accessed Feb. 14, 2011.