No, you should have both the tTG-IgA and total serum IgA tests to screen for celiac disease. As long as you produce IgA (total serum IgA confirms you do), tTG-IgA is 98% accurate in measuring elevated antibodies. If you’re IgA deficient, or if there is some other equivocating factor to potentially compromise the blood test, then an EMA blood test is also given. March, 2016