A tissue transglutaminase IgA (tTg-IgA) test is used to help doctors diagnose celiac disease or to see how well people with the condition are doing.
What is celiac disease?
Celiac disease is an autoimmune disorder in which the immune system mistakenly thinks that gluten – a protein in wheat, barley, rye, and oats – is a foreign invader.
The immune system makes antibodies that attack an enzyme in the intestines called tissue transglutaminase (tTG).
Celiac disease affects approximately 1% of the worldwide population.
The finding of tissue transglutaminase IgA antibodies is specific for celiac disease. For individuals with moderately to strongly positive results, a diagnosis of celiac disease is likely and the patient should undergo biopsy to confirm the diagnosis. The finding of transglutaminase IgG antibodies may indicate a diagnosis of celiac disease, particularly in individuals who are IgA deficient. For individuals with moderately to strongly positive results, a diagnosis of celiac disease is possible and the patient should undergo a biopsy to confirm the diagnosis.
The treatment for celiac disease is maintenance of a gluten-free diet. In most patients who adhere to this diet, levels of associated autoantibodies decline and villous atrophy improves. This is typically accompanied by an improvement in clinical symptoms.
tTG ANTIBODY, IgA
<4.0 U/mL (negative)
4.0-10.0 U/mL (weak positive)
>10.0 U/mL (positive)
tTG ANTIBODY, IgG
<6.0 U/mL (negative)
6.0-9.0 U/mL (weak positive)
>9.0 U/mL (positive)
The finding of tTG IgG antibodies may indicate a diagnosis of celiac disease, particularly in individuals who are IgA deficient. For individuals with moderately to strongly positive results, a diagnosis of celiac disease is possible and the patient should undergo a biopsy to confirm the diagnosis.
If patients strictly adhere to a gluten-free diet, the unit value of anti-tTG antibodies should begin to decrease within 6 to 12 months of onset of dietary therapy.
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