Contributed by Healthians Team
What is Tissue Transglutaminase IgA, IgG test?
A tissue transglutaminase (tTG) IgA and IgG test is used for the evaluation of autoimmune conditions developing in your body. Celiac disease is an autoimmune condition. If you are suffering from celiac disease, then your immune system sees gluten as a foreign invader and attacks it. Gluten is a protein found in wheat, barley, rye, and oats. This response by your immune system involves the production of antibodies which is directed against an enzyme that is normally present in your intestines and is called tissue transglutaminase (tTG).
In celiac disease, your body produces two types of antibodies that attack tTG immunoglobulin A (IgA) and immunoglobulin G (IgG). Measuring the IgA form of tTG antibody present in your blood is more useful in detecting the disease as it’s made in the small intestine where gluten causes inflammation. Levels of the IgG form of tTG antibody can also be used for the test.
Who should get the test?
These medical examinations are prescribed if you have signs signifying celiac disease, malnutrition, or malabsorption. These signs are often nonspecific making the diagnosis difficult. They might go unnoticed and then worsen over time creating difficulties for you. This condition can affect different parts of your body.
Digestive signs might include abdominal pain and distension. You will get a bloody stool, chronic diarrhea, or constipation including flatulence and greasy, foul-smelling stool. You might also experience vomiting. Apart from this you also suffer from iron-deficiency anemia which does not respond to iron supplements. You might have easy bruising or bleeding coupled with bone and joint pain. Your body can indicate signs such as defects in dental enamel, fatigue, weakness, infertility, osteoporosis, mouth ulcers, and weight loss. Celiac disease tests are prescribed to your children when they exhibit delayed development, short stature, and failure to thrive.
Why is the test needed?
You might be suffering from the celiac disease if you have itchy blisters on your skin. A tTG-IgA test might be conducted if your child has symptoms such as poor growth, belly pain, constipation, vomiting, diarrhea, or rashes. It is also done when your child has a condition that makes the celiac disease more likely such as type 1 diabetes, thyroid disease, or a family history of celiac disease.
These antibody tests might be prescribed if you have been on a gluten-free diet for a period of time. This is done to validate that antibody levels have reduced and the diet has been impactful in reversing the intestinal lining damage. You might be tested if you have a close relative who is suffering from celiac disease.
What does the test result mean?
The blood sample gets processed by a machine and the results are commonly available within a day or two. The doctor performs further tests in case of a positive report. The reference range is given below:
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)
Reference values apply to all ages.
How is the test done?
To get accurate results your child must eat a diet that includes gluten-containing foods such as bread, pasta, and baked goods. The child’s body will produce antibodies when exposed to gluten. Blood is drawn from the vein after the skin surface is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure for blood collection. A needle is inserted into your vein and the blood is collected in a vial or syringe. The procedure takes few minutes.
